May be a dumb question but I want to teach my daughter correctly. We are getting ready to start collecting eggs for eating & hatching. What is safe to write on the eggs with? Regular pen, pencil, sharpie. What is safest? She is doiing a 4H project of selling eating eggs, hatching eggs, & chicks & ducklings. We have hatched before but I need to make sure we have wrote on them safely before I think I have used what ever was closest & wrote well.