Clean them? All we do is crush them (and not always that until I dig in the compost).

No need to clean... just break up and bung in the compost.

They decay better if a little bit of white and membrane is left on them, and the compost will be richer for it.

BTW so far as I know worms don't eat egg shells but they will, eventually rot down.

Thanks
Moon Grower Worms do eat eggshells thy love them all ways put them in my Wormery for my compost ? Cheers

I always wash them in soapy water first then I save them through the winter for crushing and putting round hostas in pots next year. The "shell" effect usually works till late August/early September so the slugs obviously don't like to crawl over them. Never tried them in the compost though.