After completely draining a motorcycle fuel tank of gasoline, I packaged the tank and took it to the local post office for shipment to the buyer. The women at the counter started to weigh it, and then smelled the box, and asked what in the hell was going on. That all the gasoline was drained, and that the smell was clearly due to inevitable residual vapors, was not accepted. She proudly said she couldn't take it, with a smile on her otherwise miserable face. So I went to the post office a town over, and there were no problems. Basically, I really hate people that feel they need to act powerful and throw a wrench into your day over petty issues.