Odd or unusual gifts from customers...

(That aren't an STD or offspring). I had a customer that I replaced an old mercury thermostat for. He was looking over my shoulder the whole time, as I always encourage and enjoy, and he asked what I was going to do with the old one. I explained bringing it into wholesaler for collection. He said "oh I got something for you then" and disappeared. I'm packing up truck and be comes struggling out of an outbuilding carrying a milk crate full of mayo jars full of mercury. No idea where they came from.