Distinguishing between polyethylene and polypropylene plastic food packaging for recycling

I want to recycle as much food packaging plastic films as possible (I’m willing to clean and dry them). As far as I know, food packaging films are only made from 3 types of plastic: polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC). Only PE is recyclable and collected by grocery stores. I can identify PVC film because it sinks in water, but I’m having trouble with the other two types. I only know of one theoretical difference: PE makes a soft rustling noise when crumpled, while PP makes loud crackling noises. This is not helpful in practice because I’ve seen thick PE film make noises that are just as loud of PP film. Are there any other ways to tell them apart, using only common household objects?

I think thin PE film is also stretchier than thin PP film, but I think thick PE film is non-stretchy, so that doesn’t help either.

The films I’m specifically interested in are:

• Vacuum meat and poultry packaging, like the thick bags whole turkeys and pork ribs come in
• Vacuum bags for individual frozen seafood portions, like salmon fillets
• Vacuum packaging for dairy products, e.g. fresh mozzarella and Parmesan wedges

While I’m on the subject, suppose a film is PE; is there any other reason it may not be recyclable? I know frozen vegetable bags can’t be recycled because they have a low-temperature additive. I also know stickers and anything that isn’t PE need to be removed. Anything else I should watch out for?

Thanks in advance!