This is not in reply to anyone in particular but something that I want to keep in the forefront of my mind.
Plastic, greasy or not, bags or not, when discarded take a LONG time to disintegrate/biodegrade, if ever.
That's my main reason for wanting to switch to glass and to avoid plastic. That AND the grease!
I'm not proposing that everyone should think like me, though.
HowStuffWorks "How long does it take for plastics to biodegrade?"