Shadow angles will get you every time lol. Had a batch of scanned wedding pics where the model called a lace tablecloth a "chain link fence" and my uncle's bald head got tagged as a "basketball." Old scans are just rough on these models. Your grayscale check idea is smart though, might steal that.

Congrats on discovering the ancient secret of "stop buying stuff you don't read," truly groundbreaking wisdom from Dale. Next he'll tell you water is wet and you should pull your pants up before leaving the house. Kidding aside, the 3 issue rule is solid and it's wild how many people never do the math on their pull list until they're buried in floppies they never open. I did a version of this a couple years back and dumped like 8 titles in one shot, and my wallet has been thanking me ever since. The part about actually being excited for the books you keep is the real win, because a stack of unread comics just turns into guilt with a cover price. Six books you love beats fourteen you're just checking off a list, no contest.