Sorry, I misread your original post.

I'm guessing that the only way they can run the processor efficiently is with a single type of plastic at a time to reduce the variability.

Sure, they can process mixed plastic, just not efficiently.

It's a guess on my part, but I think that's where they are at.

If they know enough about the feedstock going in, they could probably determine how to process it somewhat efficiently even if it is mixed.

But I doubt that an unknown feedstock of variable plastics can be processed well.

Note, this has nothing to do with the sludge claim on the other board.  It has to do with processor efficiency.

Do you have any doubt that it easier to process some plastics than others?