Can I recycle pizza boxes?
Unfortunately no, because of the grease.
Greasy or food-crusted cardboard (and paper) are not recyclable because oil interferes with the paper recycling process.
To recycle paper, manufacturers use a pulping process which mashes the paper back into cellulose fibers- using water. When oil enters the stream the quality of the new paper is diminished, sometimes to the point of being worthless.
So pizza boxes are trash?
Not necessarily. Often the tops of pizza boxes remain grease free thanks to those little plastic triangles that prop them up. If that's the case, tear the top off and recycle it!
Tip: Greasy cardboard can be composted. Tear cardboard into small pieces to speed up decomposition.
Those little plastic triangles aren't recyclable, btw. When it comes to recycling plastics, anything smaller than 2" is highly unlikely to get sorted properly. Rather it ends up as 'residue' and goes back to the landfill.
Hard as it may be to stomach, it's best to put small plastics items directly into the trash can*. It's better to avoid the cost and energy of a spin through the recycling facility - and then to the landfill. It's a double whammy.
*An exception is plastic caps, which should be recycled on the bottle.
On the other size spectrum, there are large plastic items that can be recycled, that are often missed. Check out these 5 Extra Large plastics that belong in your recycling bin.