I usually just check for the minor ones that are in near BU condition that I sort by years. During times that I can not get bags I go through them under a stereo microscope. Even when I find a minor one there is only a small chance that it is listed. The unlisted ones I keep in ziplock bags. If it is one that I think will show up in a listing later, I keep those in tubes. I don't have much interest in finding minor ones in below AU condition. Even if I find one it probably won't ever be worth much.