I hate throwing away a perfectly good box. I just hate waste. However I'll spray them down and leave them in the garage for a couple of months before I'll reuse them. I actually got a load of mites one time from someone reusing a snake bag, It was unfortunate because the guy is actually a very concientious breeder, he didn't realize someone else had shipped him snakes with mites until I called to let him know. I'll reuse bags too, but they go through the washer first on the sanitary setting.