If you still have the air bags in long chains, set up a plastic resin table or something else you don't mind getting scratched up. Then, put a box cutter through the first bag in the chain to pop it, but angle it down so it sticks in the table or is sitting close to it and then pull the chain of bags through the blade. You need the blade to be really sharp, but this is the easiest way that I found to break them down easily. The other thing I've done is bag them up in 70 gallon yard bags from Home Depot and take them to my local UPS Store. They're always happy to take them.