Pizza delivery boxes (with excessive grease) should be placed in the trash. They are also accepted at the food scraps (organics recycling) collection sites for free.
Pizza delivery boxes (without excessive grease) should be placed in your curbside recycling bin.
Frozen pizza boxes
Most freezer boxes today do not contain a plastic lining or plastic fibers. Therefore, most recycling haulers accept freezer boxes. However, contact your city or recycling hauler directly for specific guidance.