Answer:
You can take the parts to a scrap yard and sell them. You can list them in your local paper's classified adds. You can pile them in a heap on your driveway or front lawn with a big "For Sale" sign on them.
The problem that you have is that it may not be legal in all jursidictions of the US.
Here's the thing, aside from a few parts with the VIN stamped or cast on them, there is no way to identify what vehicle the parts came from. It could be chancey, but I suspect the law enforcement in your area is no different than anywhere else. They either have bigger fish to fry, or they are distracted by their own desires.