Ah so you have quite a few of those after all, nice stuff.
ahah 90 cents... and some guys asking $30+ per game these days on ebay, they normally never sell of course
Did you ever scan any carts for the games you own btw? It would be pretty cool to use them as bezels in MAME.
Regarding the filters I'm sure someone else can give you good advice on the better way to scan them, are the filters detachable from the carts? If so that would certainly make it easier to scan.