I always wash my hatching eggs and have always had good results, to me it's better than looking inside the bator and seeing nasty eggs which will do more harm than washing them because of the bacteria growth. I don't have to wash or lightly rinse but a few out of every 2 dozen egg's but still I don't like the idea of any dirty eggs in my incubator. The key is to lightly wash and rinse the eegs with very warm or hot water so the bacteria doesn't go into the egg as it does when using cold water. If washing eggs were bad then why do they sell commercialy available egg washing solutions, that even hatcheries use. it is also a good idea to keep nesting area's and boxes clean then you won't have to wash eggs.