Lets say a coin is graded as a au55(not slabbed) but has been cleaned or has a scratch, how far does it drop it in the price guide? Would it go to a au50 our a vf?
I listened to a "The Coin Show Radio" episode where Matt discusses this topic, and how much to discount a problem coin. Might be worth a listen. http://www.coinshowradio.com/Episode_55.html
It depends on who is considering buying it, the severity of the problem, the type of problem, the scarcity of the coin, and how badly the potential buyer wants the coin. In other words there is no rule of thumb because there are too many variables. But there is a general range the value will fall into. Problem coins can bring anywhere from 80% to 20% of what a similar problem free example will bring.
