Just had a horrible case of loads of maggots in the bin, it came from left over cat food. Then bin not emptied twice. It was disgusting. Searched and found the best remedy. SALT, its killed them quickly and very cheaply. I sprayed a weak bleach solution all over and they were still crawling. They crawl up the inside of the bin. So spayed everywhere and then poured loads of salt in, and around the rim of the bin. Its worked brilliantly.