I wish I had known how to clean them before incubating too. Last month I bought 6 Silkie eggs through ebay that were not well packaged. On arrival one egg was crushed and the others were covered in dried yolk. Three eggs never developed; one chick made it to internal pipping and died, and the last one hatched and died 24 hours later. So heartbreaking. Now I'm incubating Cream Legbar eggs from a local seller and one of them is filthy - covered in dirt and dried feces. I brushed off what I could but am frankly worried. Oddly enough though, this egg so far is developing on schedule while a couple of the others are not.
Darn I’ve already set them in the bator. I cleaned them off as much as I could so I’m hoping for the best. Thank you for the advice. Now that I know I can sanitize eggs I’ll be doing that from now on!