I'm a fairly new chicken mom, but I don't either since my girls are tidy and don't poo in the nest boxese so the eggs don't get dirty. From what I've read here on BYC, washing removes the bloom and makes the eggs age faster so unless they're really yuckyit's best to let them be.
When I used to get eggs from my neighbor they were usually covered in poo. My chickens started laying a couple weeks ago and NONE of the eggs have poo. Even today, when we got home from church, there were three eggs in one nest and NO poo.
What's different that would cause the poo ~vs~ no poo eggs?
One of my barred rocks seems to get a dirty butt - I've had to clean her a few times. When her butt is dirty, there's a bit of poo on her eggs. I don't wash them until ready to use. I also don't give those eggs away - I don't want anyone else to have to deal with my dirty eggs!