You can go here to read about microchamber paper - http://www.conservationresources.com/Ma ... hamber.htm
CGC puts a sheet inside the front and back covers of every comic before slabbing. I also do this with the books I store in mylites.
As far as the rust on the staple is concerned, I think the environment in which you store the comic is the most important factor. Initially many people worried that storing a comic in an enclosed CGC case wouldn't allow air circulation and that gases from the paper and humidity could build up inside the case, damaging the comic. I have never heard of this actually happening. I have seen photos of comics in CGC cases with terrible rust on the staples, but these were stored in safes. Apparently a home safe is a very poor environment for storing metal as the humidity promotes rusting. I've heard that guns stored in gun safes need to be oilied or they will rust. On the other hand, safety deposit boxes seem to be OK as they are in a controled humidity environment.
You can always call CGC and ask for the grading notes on your comic. If they mention rust then it was there during the grading. If they don't mention rust it is possible that it has formed since slabbing (although it is also possible they just didn't mention it in the notes).
Realistically, your DD 111 is worth about $30 so why not crack it out of the slab and enjoy it? I take almost all of my comics out of the slabs so I can read them (unless I'm planning to upgrade), but many other people slab their raw comics even though they aren't for sale. This is something I don't understand, but to each his own.