rusted bottle caps

This seems like a really dumb question, but here goes...

I went to bottle my second batch about a week ago and found that roughly half the caps i had leftover from my first batch decided to rust. I had bought a gross of regular bottle caps for the first batch, after my roommate's dog ate the ones with my kit (which was bottled in early february) and had around 90 leftover. I stored the caps in a ziplock bag in a drawer in the kitchen. When I went to bottle mid-march I had to do a mad dash to the LHBS to buy new caps. The $3 i spent on new caps wasn't going to break my bank, but it still irked me. Has anyone else had this problem? Is there anything I can do to prevent this from happening again? Is it worth me paying more for the oxygen barrier caps (i.e. do they really do anything for me)?


Thanks

If you put leftover wet caps in with the ones that were dry then that is why they rusted. Next time set all the wet caps on a paper towel to airdry overnight or just toss em since they are so cheap. This happened to me a few brews ago. Not sure I even know what oxygen barrier caps are. Don't all caps work the same?

I am skeptical about those oxygen barrier caps. My LHBS claims that they really do absorb oxygen inside the bottle, but for the life of me, I can't see how. You are supposed to activate them by simply wetting them, but that makes no sense to me. There is always moisture and oxygen in the air, so why wouldn't the caps react while you are storing them? When you buy them, it is not like they come vacuum sealed or anything.

Anyways, if you bottle your beer but just set your caps on top for a while, the priming sugar will actually ferment immediately, and CO2 will start to form, pushing out any oxygen in the bottle. I always wait about 15 minutes before securing my caps for this reason. Plus, all the active yeast in the bottle will eventually consume any O2 that diffuses down from the headspace anyways. So I think the O2 barrier caps are just a worthless gimic -- get the regular ones.