Recycling pizza boxes are only an option if there is literally no organic material traces in the box which is very rare. There are some environmentally conscious pizzerias’ that will place wax paper or foil in the box so that grease and cheese do not contaminate the box.
Organic material (meats, cheese, grease, etc.) start to decompose quickly, which also causes the cardboard to decompose therefore making the cardboard impossible to recycle.