Cartridge storage & humidty


Does anybody have any information on humidity “safe-zones” for storing cartridges in typical flat file drawers at certain humidity levels, or what humidity levels in general are safe for brass cases? I’ve been doing some experimenting over the past year with cartridges left in various places at different humidity levels and have found different results. Some cases (particularly starline brass for some reason) seem to have a sort of rusty corrosion that faintly takes place in as little as 6 months if they are stored adjacent to materials that hold moisture like cardboard, or some foam liners. Sometimes it seems to take place even if they are not stored along with cardboard even. Other cartridges that I have left out in the open on a wooden work bench in my basement for over a year show no such signs of discoloration. When the rusty-colored discoloration does occur it often seems to follow fingerprint marks which were previously not visible on the brass case which leaves me to wonder what chemical reaction concerns might be going on with oils from sweat, etc… These cartridges I have experimented with were various cheap ball rds that were all fairly shiny and new to start with. I have also noticed that nickel-plated brass suffers no such condition issues under any circumstances so far.

Has anybody ever tried to clean such rusty discoloration from brass, and what did you use?

Any other experiences from anybody else with certain drawer liners or cartridge display methods?

What do you guys do for humidity control (absorbing chemical baskets, or moisture absorbers in drawers?)

I had started a couple years ago on setting up all my cartridges for display in drawers, but then backtracked after realizing I needed more space and wanted to experiment with storage conditions for brass / steel preservation since I have a good handful of cartridges with exposed steel as part of the projectile.



How high is humidity in Maine!? I have central air throughout the house and a dehumidifier in the basement. I also bring dessicant bags from work and leave them everywhere (my company receives a continuous flow of bulk chemicals with these dessicant packs inside). The same chemicals come in plastic buckets with moisture gaskets, which are great for bulk ammo storage. Anyone driving through New York with a need for dessicant bags, just yell!!!


I really like these.

When they become too absorbed it lets your know and then you can recharge them in your oven.

Each one is good for 3 cubic feet which is plenty strong enough for a flat file drawer.


It’s actually relatively dry for 9 months of the year in Maine, but in the summer months we do get humidity, mostly July & August. My home situation leaves me little where else other than the basement to put everything which can be more humid than other parts of the house, but I do run a dehumidifier down there. I’m looking at moving the collection to my work since there’s an alarm system there, and I’m there with plenty of spare time 7 months out of the year anyway. The work location is much drier, but I still would want to put some kind of desiccant baskets in the room for summer months - maybe a dehumidifier. I have also wondered if too many dehumidifying desiccant packs in drawers can be bad if not monitored very closely as in them creating a humidity vacuum once they get full and need to be switched or dried?

I think my main concern lately is whatever the rusty colored reaction thing is on some of those brass cases, whether it has more to do with fingerprints or humidity? I’ll try to get a picture up of what I’m referring to soon. The answer to the question might come from somebody who may have noticed this reaction in a very dry place like Arizona, which would suggest it’s more about the fingerprints / oils reacting somehow.


Those desicant canisters are only good for sealed containers made of material that does not itself absorb moisture. For example, they do not work at all in wooden boxes. They have a very finite ability to absorb moisture.

The bottom line is the Maine basements get very wet in Summer. I run a dehumidifer June, July and August for a couple days a week. Unless you button up the windows of your house, there is no real point running it more than that as you simply can’t keep the humidity lower than ambient. Running one for a few days a week keeps you from building up really high levels. Without one, you can easily see 85% in your basement. Once I started running a dehumidifier, all my basement moisture problems went away. Cost in electricity is about $20 a month. Well worth it!



My collection is in an out building and kept mostly in a metal drawer cabinet. Had a serious mildew problem come up on my paper shells so I went with a dehumidifier. A window AC draws in moist air and the dehumidifier fights it I guess but keeps my moisture down around 50-60% which seems to be fine for guns and shells. Place doesn’t have dank smell either. Course, I live right on the Atlantic coastline too so humidity is a way of life here in the summer.