How long have cards been trimmed?

[FrankWakefield]

If the idea is 'how long' with intent to improve value, then what Jeff says about 'as long as any type of money has been involved' would be the answer. And cards started getting a 'bit' of value in about 1960 or so. I'd think before then, when HOF T206's sold for under a dollar, things weren't out of hand. Burdick, Carter, Orem, the old guys... they'd whine about folks paying very much at all for cards. The value of them interfered with their collecting of them. So in the 60's and 70's, when folks started getting more for the cards they sold (careful there, to avoid saying that cards were 'worth' more, cards are just cardboard), THAT would be when trimming, coloring, bleaching, and such began, with a goal of deception to get more money for a sale.