"Artists Beware"

When I bill for shipping unclaimed artwork that bidders didn't pick up at the Anthrocon Art Show, I call it "shipping expense" which covers not only the postage, but also the cost of packaging material (boxes, packing peanuts, bubble wrap, etc.). I weigh AND MEASURE the package and use the online calculator. I've gotten bitten a couple of times by the dimensional weight -- I bought a bunch of cartons that were 24"x5"x18" which triggered it. Unfortunately it's a hassle to cut down the carton to 3" deep (which makes it cheaper) but I feel guilty about having to charge the more expensive rate if the artwork will fit in the shallower carton.