Depends what you are trying to get of and why. Do you have an alko ball & hitch? if so it needs to be clean & grease free - just use "wet or dry" abrasive paper and wipe it with a clean dry cloth.
i have a alko hitch on my van but a non alko tow ball does this mean i have to make sure the towball is grease free ??? (it has a towball cover when not in use .