Also dull is a very relative term in that there are many different levels of dullness just as there are many different levels of sharpness. If a razor has no edge then it will take a LOT of work just to set a bevel and get the razor to a level of knife sharpness. Many razors will also have chips in the edge and/or corroded steel which could take a lot of work to work through before you even reach the good steel that will take a quality edge.