Ideally you would incentivize people to create less trash by charging them by weight or volume for collection, but there are two possibilities for households wanting lower bills: reducing waste or littering. And it only takes a few people choosing littering to make a huge mess.

I'd try to collect payment for disposal earlier. If you pay for disposal when you buy the product, it makes doing the right thing easy. It also makes products with wasteful packaging more expensive right there in the store, encouraging people to buy less wasteful alternatives.