A friend of mine washes all of her eggs and has excellent hatches. When you think about how clean you would like to have your incubator when you start out why would you want to comtaminate it as soon as you start.
That's what I'm curious about...................What would I be rubbing off?
If you rub them too hard, you will rub off the bloom, which is a protective coating that is on the egg to keep bacteria out. Just run or dip them under warm water and wipe lightly with a damp cloth.
I have some coturnix eggs in my bator that are just plain nasty, they are still developing