@unksol My city used to accept grease-stained pizza boxes as long as there was no solid food. At some point they stopped taking them, which I didn’t find out until I was searching to see if something else was recyclable.
Our local recycling company makes a distinction between frozen pizza boxes and delivery/take-out pizza boxes. No to the frozen, Yes to the delivery/take-out. Their website has a handy little function where one just types in the item and gets the answer.