Flow with the stream don't try to fight it.
Right now how I view it the problem is it is a matter of just keeping up with the trash and making it easier for those that actually haul it out. This is the easiest path because it is currently being done.
Informing others, being vigilant about what people leave behind and putting systems into place would be the next step IMHO. It is much harder to wake up the unenlightened than work with those that are.