I have been using poly bags that came with some of the books that were purchased at my comic store. How often should they be changed?
We have heard horror stories from collectors who, after only one month, have seen their bags and comics turn yellow. If poly bags are all you can afford, then they should be changed at a minimum of every five to six months. This, however, can cost more than if you initially put them into Mylar®, which never have to be changed.
