That's not nice. Maggots can end up in your waste bin. This has a lot to do with the type of waste you collect in your waste bin. Various insects are attracted to the types of waste. Once the bugs get into it, they are very difficult to get out. For example, they crawl under the beading edge and settle down/hide there. It is important to thoroughly clean the waste bin or lid (right where the problem is) with water, and to use the water hose. They don't like this, and then crawl out on their own. Then allow the lid or waste bin to dry well (preferably in the sun).