I read that the M1 carbine magazines are prone to corrosion.  What do you do to minimize the start of corrosion?  How do you store them?  Clean and oil after use?  Don't worry about it?

I just received two rusty GI mags with a new canvas pouch that fits over the buttstock.  I think the mags are "IA".   I would say to store mags dry with normal oiling like gunmetal.

My problem with mags has been they drop out of the rifle as I shoot them.  GI 15 rounders are ok in my Plainfield rifle but 30 rounders and aftermarket mags have been falling out.  I may be making progress on this issue as I have noticed the magazine catch does not always return to the original position when a mag is loaded.  Maybe my mags will stay in if I make sure all is well with the magazine catch.

If I am not mistake, you need a m-2 magazine latch to keep the 30 round magazines in place.  The original m-1 magazine catches usually only work with the original 15 round magazines. I have seen the m-2 catches listed at both Orion 7 and Fulton armory.  I think that they run about $10 if I remember correctly.