Which bin for eggshells?
Usual answer in the UK
Food waste Food waste caddy
Eggshells go in the food waste caddy, or on the home compost heap.
Also possible: Garden waste bin.
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.