[sciclaw]

I'm genuinely curious... If the pizza box is greasy, I tear off the bottom (some boxes are perforated to make this easy even) and toss that in the green bin, which is allowed where I live. I assume anything not greasy/dirty can be recycled. Am I doing it wrong?

[sokoloff]

Our municipal recycling is clear that pizza boxes with grease staining can still be recycled. Other places are equally clear that cardboard has to be free of grease, so you'll have to check with your local waste collection to be sure.

https://www.cambridgema.gov/Departments/publicworks/getridof...

[TillE]

As always, check with your municipality. But yes generally heavily stained paper should not be recycled, but the rest can.