Which bin for pizza boxes?
Usual answer in the UK
Recycling Mixed recycling bin
Clean parts of a pizza box can go in recycling. Tear off any greasy or cheesy section and put it in food waste or general waste.
Also possible: Food waste caddy; General waste bin.
Common mistakes
A small grease stain is fine in most areas. Food left in the box is not.
Does every council do this?
Most councils follow the answer above, but bins and sorting rules are set locally, and a few councils still do things differently. If your bin has a sticker, or your council sent a leaflet, follow that. Enter your postcode to go straight to your council's guidance.