Commercial egg producers wash their eggs for a reason. If they were to attempt to sell dirty eggs they would soon be out of business. More important than just providing the customer with a clean looking product, eggs are washed to remove the bacteria from the shell which will penetrate to the inside during storage.
The theory that the natural protective coating on an egg shell should be maintained should not be given much consideration unless the shell is 100 percent perfectly clean. Leaving that protective coating on a dirty egg will accomplish exactly the opposite of maintaining egg quality in storage.
The dreaded Salmonella bacteria, which can cause food poisoning can be avoided by thoroughly washing eggs. Eggs that are washed in hot water and kept refrigerated will keep for a month or two with no problem.