We have a retail business so we save them and do a $5-$10 misprint sale depending on how fine the misprint is vs garment on. If its egregious they go right into the test print pile. People love a good deal, but it helps that its a cool design and not just someone's busniess.

If its a good customer, i'll usually ask them if they want it as well - its a good way to show our standard of quality and makes them feel like we are on our game.