For $20.00, I'd just toss'em.
There really is no proper way to simply toss them.
As for the blanket over the tumbler, I like the idea for the purpose of a blast, but that kind of sounds like a fire hazard.
IMO, the best course of action for this problem is a huge popcorn bowl... a damp cloth... and sit down in front of a movie and wipe down each by hand.
After wiping down 700 pieces, each by hand, you might have yourself fully trained to NEVER drop them again!