RCH-Thanx, bro! Wow! you must have humidity beaucoup in the Phillipines. We got plenty too here in central Ohio. Between the forests, streams, creeks, and corn crop, it just "holds" the moisture. I live in a valley witha creek at the bottom. Rel. humidity often 80-90% here in the summers.
Second the notion of putting up your ammo cans up from cement floors. Moisture migrates up. I laid some "treated" 2 x 10 over briacks or cinder blocks on the floor of my basement and stack the .50 and .30 ammo cans on top of these. I put a thermometer and hygrometer down there too. A steady 72*F at 60% rel. humid. with a cheap dehumidifier running 24/7. [Army suggests 40-60% rel. humid, but I'll never pull 40% here. I can get 60%.]
TRICK: mark the ammo can with cheap masking tape on each side/top and bottom and magic mark what's inside directly onto the tape. Later, if you wanna change loads in the can, just rip the tape off and put new tape on. Sure beats marking all over the can!
Sometimes when I am really whacked, I use the freezer gauge ziplock bags to "line" the ammo cans even tho they have the rubber seal (which I treat with a silicone ploymer like "Armor-all," or "Son-of-a-Gun" silicone] OK, OK! It must be the Boy Scout in me or somethin else.
Anyways, my ammo stash will outlast me and I breathe easy knowin my kids and grandkids will be using my stuff I store up. If the Liberals ever get back the Whitehouse and Congress, ammo will be $1-$10 a round! (Don't laff--ask Sens. Schumer or Feinstein with their wacky bills)--my kids will be multi-millionaires!
---Woody---