I rarely ever wash any egg.
And i definitely sell them unwashed because tests have shown that unwashed, refrigerated eggs last the longest, and if my customers leave their eggs in the fridge for 6 months, i want them to still be good when they finally get used......though that length of time is very unlikely. My customers LOVE to eat my eggs.
If i have an egg that is really dirty, as in someone pooped on it, i set it aside for personal use, and i wash it in very warm water right before i crack it. The warm water causes the egg to expand, pushing bacteria out. The cold water causes the egg to contract, pulling bacteria in. I use water that is warmer than my egg. I read about one person soaking their eggs in hot water, and i would definitely not recommend this. As this person learned, i think, soaking in hot water begins cooking the eggs slightly. If i have an egg that is so dirty it must be washed, i don't sell it.
The very best protection you have for the inside of your egg is the natural bloom. Tests have confirmed that.
Also, it is true that unrefrigerated eggs are better for cooking. I leave my eggs in a basket on my counter. If i get more than the basket will hold, i rotate the older ones to an egg carton in the fridge to be sold, and i fill the basket with the newer eggs. This also allows me to choose eggs for incubating that have not been washed or refrigerated.
http://www.motherearthnews.com/Sustainable-Farming/1977-11-01/Fresh-Eggs.aspx
Here is a great article you might enjoy reading.
**one last thing, i would say that if you're using your eggs within say, 2 weeks or so, it probably doesn't matter whether you wash them or not. that's just my personal opinion. it's the longer periods of time in which these things start to matter more.**