I have a friend who works for a construction company. He is one of the head maintenance techs both in the shop and out in the field. He said they still have a few older 7.3 Powerstoke that gets sent out every day. He told me all they do with the fuel filters is remove them, then clean then in a solvent and reinstall them. This does not seem like a good idea to me, but then again I am accustomed to gas engines. So is this a good thing to do, or should I keep buying new filters as apposed to reusing my old ones?