It’s very important that you never put a type of plastic that your hauler doesn’t accept in with the rest of your recycling. This is a form of contamination in the same way that throwing non-recyclable waste or food in the bin would be. It can result in a ruined batch of recycled plastic, or in otherwise perfectly good recyclable material ending up bound for the landfill. Also, plastic bags (a form of #4 LDPE) can get caught in sorting machines, resulting in lost time and costly repairs. Unless your waste hauler explicitly says otherwise, plastic bags should never go in your recycling bin.
The good news is that there may be drop-off or mail-in programs available for types of plastic that aren’t accepted in your area. Supermarkets often have drop-off receptacles for clean and dry plastic bags to be recycled safely. Other programs include Preserve’s Gimme 5 for #5 plastic and the EPS Industry Alliance’s recycling program for #6 plastic in the form of expanded polystyrene, as in packing peanuts and similar goods.