Letter Re: Long-Term Caches

Dear SurvivalBlog,

I have searched your databases and even some youtube areas, but see much conflicting information. I was going to use a plastic bucket, but found out they are not rodent proof, so I am moving to the coated ammo cans. The primary question is regarding firearm storage. Some say to grease them, others don’t mention anything. Would putting them in a sealed bad work? I would think you might not have the time to clean a greased gun. What about storing any gun oil? I have also heard lighting a tea candle right before sealing it to get rid of any oxygen inside the container is a possibility. – Dan

JWR Replies:

Yes, use a plastic bag and plenty of oil and grease, especially on the face of the bolt. But be sure to enclose an index note card that says: “WARNING: Grease In Bore and Chamber — Remove Before Firing!!!” A cleaning rod, patches, and oil should accompany each gun stored with this method.

Note that some wooden stocks can be stained or even soften with prolonged exposure to some oils. But fiberglass and other synthetic stocks are generally impervious.

My current favorite lubricant is Frog Lube CLP. It protects metal from rust just about as well as grease.

You can use the CO2 method of displacing oxygen, but do not use oxygen absorber packets. Those are designed for food, not metal! They actually use an oxidation (rust) process that can induce rust on stored metals in the same container.


  1. Up until recently, I’ve been in the “If it’s time to bury them, it’s time to use them” camp, though recent events have compelled me towards other avenues. 8 inch PVC pipes are cheap, for now….

  2. Ammunition should be stored and sealed separately. Gases given off by petroleum products can penetrate and degrade primers and powder.

    Never bury on your own property…

  3. Some people put the gun in a bag and then put most of the bag into water so he wight of the water helps remove the air in the bag. The only problem with this is you may get water in the bag. It’s a lot safer (from a rust point of view) to use children’s play sand. You can use any sand but by using children’s play sand you will know that it is clean and has nothing sharp in it.

    1. most vacuum sealers include hose to seal jars. this can be used to remove the air from the storage . I have an impulse sealer which is used to seal bags after vacuuming.

      1. The problem with vacuum-sealing ANYTHING exposed to moisture is that if the membrane is breached, the vacuum will suck moisture IN. It’s be better to PRESSURIZE the vessel with nitrogen.

  4. When the heat was on during the Sotero administration, I employed Z-Corr bags inside well-sealed 55 gal drums. I have yet to exhume any of these caches but would appreciate any info regarding results others may have had. A supposed advantage to the Z-Corr products is that the contents need not be heavily lubed and than thus be immediately used in extremis without cleaning.
    I took to heart historical accounts of Israel”s war for independence during which the situation was so desperate, newly arrived firearms still coated with Cosmolene were issued with the result that some lost their lives because the weapons would not function.

    1. Yes you can. The problem is that vacuum seal bags can (and do) occasionally fail. Since the cache is most likely not easily available, routinely checking for this type of failure is problematic.

      1. FWIW your mileage may vary. On an unrelated project I am using a small 12vdc vacuum pump from amazon to insulate a water pipe. As HJL states vacuum seals can occasionally fail (any solution can fail) run 1/2″ poly pipe from container to 12″ below ground surface or even deeper. Have a valve near the end of the pipe and a plug in the end to help retain vacuum. Check vacuum annually.

    2. Just as ‘two is one, and one is none’ never rely on just one solution to protect your cache no matter the content. Use cosmolene, two layered mylar vacuum bags, buried in sealed pvc container. Vacuum the container, check annually. DO NOT store ammunition in vacuumed bags or container as the vacuum can seep into the cartridge and the bullet can be pushed into the cartridge when the vacuum container is opened. The cartridge when fired would exceed the SAAMI pressure specification for the cartidge. And that is just not safe at all.

  5. How about oxygen absorbers (desiccant packs) in ammo cans with loose ammo? Not necessarily for cache purposes but just general storage. Will it harm the brass or other components of the ammo? Thanks.

    1. Desiccant packs are not oxygen absorbers. They are for moisture control. They’re fine for ammo storage. I put 100 rounds into a pint size freezer ziplock bag with 1 small desiccant satchel, squeeze out as much air and seal. Then place the bags into a .50 cal can with a couple more desiccant satchels. Should be GTG for years if not decades.
      DO NOT use oxygen absorbers for ammo storage. Just asking for problems.

  6. I Buried 2 new pieces of steel in my back yard to test how long they could last. Each was one was greased. Then I wrapped the items separately with 20 layers of plastic then taped over completely with clear packing tape. After 10 years I dug them up and one package was chewed by a rodent barely but enough to cause ground moisture to get inside and rust the metal. Also the grease was dried up and gone. The other one was dug up after another 10 years and still ok. After another 10 years I finally dug it up and the neighbors tree roots had gowned around it so I had to cut the roots away to retrieve it. Also since the metal was long the roots had bent the metal a lot. For metal to rust you need free oxygen and moisture. One all the free oxygen is used up there will be no more rusting. Example, fire sprinkler pipe is made out of thin metal because the water is stagnant so one the free oxygen is used up rusting or oxidizing stops. Also picture of the battleship Bismarck sitting on the ocean floor has no corrosion on it and the rear deck swastika is still intact. That’s why oil is used to stop rust because it is a barrier to keep oxygen and moisture away from the metal.

  7. We have a basement which seems to rust “everything” over time. The only research we’ve found is to install a dehumidifier and that only suppresses the inevitable. Does anyone have any recommendations on keeping a basement rustproof. We thought about installing heaters and keeping it 75 degrees down there but that comes with a cost. We have no water leaks but it’s just damp and cool down there. Your thoughts?

    1. For 10’s of thousands of dollars you can probably get your basement water proofed and the ground around it drained by a sump pump. But no doubt that is too expensive an option for you. Moving would be cheaper. That’s pretty much it.

    2. You can look into using a silica gel de-humidier. Silica gel can be used in gun safes without risk of corrosive effects. Stay away from calcium chloride which has corrosive effects on metals. Also, there is waterproof paint you can use on the basement walls but you will want to first determine the cause of the dampness. Sometimes it’s just because the cold concrete causes condensation. There are lots of videos and articles online that could help you.

  8. And keep in mind that in northern climes the ground can freeze too solid in winter to dig out. This is remedied by burying in pea gravel and then topping with a disguising layer of a few inches of dirt and leaves. A junk pile of rusted old farm tools and broadcast handfuls of bolts and metal debris on top help against metal detector hits.

  9. I would also suggest a cheap carbon steel pocket knife and or aluminum pop can to be buried between the surface and the prize. This may throw off any folks with a metal detector. Also bury unregistered firearms to avoid any perjury.

  10. While I haven’t done it, my approach would be to oil / lube well. Wrap in wax paper and cardboard. Put in a vacuum sealer bag, draw a modest vacuum on it. The cardboard would help protect the bag from sharp edges and lessen the likelihood of a bag puncture. Put it in my container of choice. Fill container with hot wax.

    I have considered the PVC pipe with a very modest amount of dry ice before sealing up with pipe end caps. I would certainly need to designate that the vessel was “pressurized” and to cut open slowly. This might be worthy of a test or two to determine just how much pressure increase / oxygen displacement would occur with measured quantities of dry ice.

  11. I recommend using Frog Lube generously, wrapping in rust inhibiting paper, inserted carefully in a study open ended plastic bag and then a length of plastic pipe (preferably black) of your choice. Include cleaning gear and don’t forget a bit of camouflage paint to match your surroundings in case the soil is disturbed.

    I like this product:

  12. What about the old tried and true method of slathering your firearms with cosmoline?.. I know its a PITA to clean off, but it protected scores of old mosins.

  13. While I agree with the earlier comment of not to bury stuff on your own property, Burying it on your brother in laws place presents it own set of problems. My brother in law completely freaked out when I suggested that I was going to bury some PVC tubes out in his back 40. OPSEC was totally blown.

  14. Metal, atmosphere and water all contribute towards some rate of metal corrosion, more commonly known as rust. Corrosion mechanisms could be described, simply, as a oxidation of metal, in which a metal oxide deposit (rust) is the by-product. Avoiding rust, or corrosion, is a function of eliminating as many of the contributory factors as possible.

    Metal should be cached with some kind of surface barrier to oxygen, and ideally water. Oil is an example of such a surface barrier, as are several other products of this type. Oil will shed water, but a different “physical” barrier (oil is a physical and chemical barrier to oxygen and water) then oil should be used, because the amount of oil or similar product needed to “waterproof” a firearm, would be expensive and lead to considerable cleaning time, which you may not have in a “something bad happened” scenario. So, oil for oxygen.

    Some variety and or combination of impermeable material, such as plastic, would be a good physical water barrier. Additionally, if the primary barrier (i.e. plastic bucket, coated ammo can, PVC tube) is breached, then there is a secondary water-repellent barrier. It should be noted that reasonable efforts should be made to remove oxygen from the inside of the secondary barrier, because trapping or leaving oxygen inside the second barrier reduces the effectiveness of the process.

    Removing oxygen from the space between the primary and secondary liner could be accomplished with a candle, as the flame will consume oxygen until the oxygen concentration is too low to support combustion. It may not remove all of the oxygen, and if there is a leak in the primary container, then you may find this was not a long-term solution. Desiccants can have adverse affects on metallic objects that are not adequately sealed, as the chemical reaction can scavenge oxygen from the metal, which is another type of corrosion.

    PVC may be the best long-term primary container/barrier storage solution, with a secondary containment of plastic, and well oiled/coated parts and firearms, but not ammunition.

    Ferrous objects might attract attention from metal detectors, so consider (as mentioned by another commentor) including a shallower decoy object, preferable something that a curious digger will happily stop and take, and leave the real prize alone.

    1. Regarding the candle, is water vapor not an exhaust product of combustion? Sounds like you’d just be removing oxygen while adding moisture to the container….

      1. Tim,
        You are correct, that water vapor is a by-product of combustion. It would be an epic battle between depleting oxygen and then adding a small amount of water.

        Candles have been used to “pressure” seal some items, historically, but have always proven less then effective.

        Commercially available products work, to varying degrees.

        I’ve had some good success with placing items in a 5mil clear plastic bag, and then submerging them in the tub, using the water pressure to displace atmosphere. It takes some practice, but it can work fairly well.

        One item never brought up, was using rice as an absorbent. Not high tech, but again old tech that has shown promise in some situations.

        In the end, its a bit of guess as to what will work the best. This is one of those situations where “overkill is underrated”. Most folks seem to want to cram a huge quantity of gear into a single container, and only have to cache once. I tend to avoid this approach, for a variety of reasons.

        Good luck,


  15. For those that are…. well…. skeptical about stashing ammo there are several brands of factory ‘canned’ ammo here are some of the manufactures; American Eagle, Fiocchi, Ready Reserve Ammo, are some of are more popular ones, I would avoid buying ANY Russian or other Eastern Bloc ammo, I’ve herd and read WAY more Cons than Pros were there ammo is concerned. Also, double check the age of American made military surplus ammo, cause of corrosive primers. Make sure when putting away your stash have LOTS OF WEAPONS CLEANING SOLVENT AND GUN OIL, WEAPONS CLEANING KIT AND A MANUEL FOR EACH TYPE OF WEAPON YOU HAVE STASHED!!!!!, I say this cause I’ve personally known people who have failed to even think about these item’s, they come in handy when you least expect it, (little brother), I bust my little brothers chops about this, but at least when I first brought up these forgotten item’s he did dig everything up and remedy that problem, (ha,ha,ha), and yes my Brother does participate on this great Blog. Like James, Hugh, and others have mentioned package it right and with ALL of the proper gear and you will have good back up gear when the SHTF. Prep right, prep for the long run, stand by, and get ready for what happens next!
    Stay Frosty my fellow American Patriots! Semper Fi!

  16. Years ago I buried a 55 gallon poly tank with a screw on lid and filled it with ammo cans of ammo. When I was getting ready to move a few years later I dug up the tank, I found it completely full of water, to my relief the ammo cans had sealed out the water in all the cans except one and all was fine. Always use multiple layers for protection.

  17. 0h no! I have a silly question, Well, I hope it turns out to be silly.

    You said no oxygen absorbers in your gun cases….makes sense.

    What about silica (desiccants)?

    Don’t even want to open the gun cases without an answer. I think I need mental/psychological preparation before I do

    Lord help me!

    1. Got my answer from previous comments. Thank you dear lord.

      I don’t own any guns of course, because they are dangerous. 🙂

      But if I did, I would most definitely have already stored them with silica packets.

  18. Am surprised there was not more mention of V.C.I. paper and bags (volatile corrosion inhibiter). Also, oven dried drywall material to help control moisture. Gallon jars with screw on lids are an intriguing idea providing lids do not corrode through, or glass is broken. Outside the box ways to address problems….

    Five gallon buckets filled with sand (dry) with a lid; turned upside down with a small ammo can in the bottom…. now on the top. Ought to shed water.

    Stainless steel second hand industrial storage boxes…

  19. If you use a nitrogen purge in a pvc tube, that should work. I use this for displacing oxygen in food storage with zero problems. You can hold a lit candle above the top of the tube and when it’s extinguished for lack of oxygen, seal the top cap. Nitrogen is heavier than air , so little to none will escape. I’d back this up with cosmolene. I had several boxes of rear u joints that were 60 plus years old, still in factory boxes. Took them to a drive line shop to see if I coul get new needle bearings and caps because they looked extremely rusted. The owner simply washed all the cosmolene out and they were perfect.

    1. Air is roughly 79% nitrogen and 20% oxygen with a few other smaller trace gases. Oxygen has a molecular weight that is about 32 and nitrogen 28. Therefore pure nitrogen would actually be slightly lighter that air.

        1. Fair enough. The functional tests I’ve done are to open a nitrogen sealed bottle after several years alongside a bottle sealed with native air inside. Inserting a lit match and dropping it into the bottle sealed with air, the match drops to the bottom and burns itself out. A lit match dropped into a bottle filled with nitrogen is extinguished as soon as it passes the lip of the bottle. That’s as scientific as I get. I’d definitely recommend cosmolene as a back up in case a sealed tube were comprised..

  20. I have been told that the English museums use a thin coat of petroleum jelly to keep their armor displays from rusting. Which is easier to remove than cosmoline. I have also read that Automatic transmission fluid makes a good gun lubricant , haven’t tried either yet. Does anyone have thoughts on this?

  21. You could pack almost anything in cosmoline and it will last for ever. When I was on active duty one of the many dirt details we got stuck with was cleaning W.W.II & Korean war era Garand rifles out of military holding to be sold later as surplus. Cosmoline gets every where and is nasty, but, yea there’s always a ‘but’, it will preserve almost any thing, including dead cockroach carcasses!

    Yo, Lineman what shaking brother?

        1. As far as day go day stuff not bad, not bad at all.
          Now you add in all this garbage of Gun Bans, School Shootings, and Corrupt Employees (our elected politicians) and …. well …. you know pretty P.O.’d!!!!, no matter which way you slice it, but other wise not bad.
          ‘Seriously!!! I wish I had that much free time on my hands…’ what’s up with that?

  22. Here is what I’ve learned from experience. If you store a metal object in a PVC tube never ever use a screw on cap. It will positively leak even if you seal the threads with Vasoline or any other lubricant. Instead use a glue on cap on both ends of the pipe. This system will positively not leak. We’re talking long term storage anyway so it won’t matter if it takes a few more minutes to remove the cap ten years down the road. I’ve also had good luck using a coffee filter filled with rice and dropped into the pipe as a means to absorb moisture. Take a coffee filter laying flat and pour dry rice on to the top of it in an amount that will allow you to fold the filter over and staple the edges together making a half round package. I have used this method inside of an Alack sack and I have stored large metal items for years outside (under roof) and exposed to the changing seasons and have had perfect success, no rust at all. And finally consider this. If you’re going to store your gun in a PVC tube on a long term basis and you want to sleep well at night knowing for sure that it is perfectly safe from rust this method is fool proof but a bit more costly. Lets say that you’re storing an AR-15 and you have your handle removed allowing the gun to fit in the tube and you’ve glued a cap to one end and you’re ready to stick it in the ground. Put your rifle in the pipe with the cap end pointing down and then fill the entire pipe full of motor oil so that the entire gun will be submerged in the oil. Then glue on the other cap. You just guaranteed that the weapon will never rust. In the future when you remove the gun just let it hang for a few hours and most of the oil will drip off. I’ve used this method for many years and I promise you it is an unfailing system. The down side is that it will cost you some bucks to buy the oil but if it cost you an extra twenty dollars for the oil and you’re absolutely protecting your eight hundred dollar weapon isn’t it money well spent? And one other benefit of filling the entire pipe with oil is that it will keep it from floating out of the ground when the ground becomes totally saturated with rain water. These are my proven methods of gun…..I mean metal storage that has worked for me.

  23. Some of the solutions offered are a bit more complicated than they really need to be.
    Since we all know that to make rust you need oxygen, a simple way to remove oxygen is to replace it with carbon dioxide in the form of ‘dry ice’. Seal a PVC pipe on one end, place rifle along with ammo, in tube, stand pipe with sealed end down, place dry ice inside pipe with open end LOOSLY sealed with an end cap, (do not glue on this cap unless you want to make a bomb). The carbon dioxide, being heavier than air, will replace the air from the bottom up and you can tell you have a full pipe when the gas leaking out of the upper end will no longer support the flame from a match. When no more CO2 gas is being released, use a screw on type plug to seal the open end. The use of a screw on end cap will greatly assist in the retrieval of the pipe contents as opposed to having to cut the pipe at some later date.

    Want to store ammo? Easy peasy. I know of some folks that use peanut butter jars. Being made of PET plastic, which is not biodegradable, just fill, seal, and bury. Peanut butter jars are of a size that fit nicely in a hole that’s easily made with a posthole digger and the 48 oz jars hold about 60 rounds of 30-06 ammo or a bunch of pistol rounds.

  24. From M-ray above:
    “If you store a metal object in a PVC tube never ever use a screw on cap. It will positively leak even if you seal the threads with Vasoline or any other lubricant.”

    Screw on fittings will/may leak if using a lubricant instead of a pipe sealant designed for use with PVC, such as RECTORSEAL. Lubricants will not seal the thread bottoms and that’s where leaks occur.

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