Is this by chance a laptop keyboard? If so did you wipe it with the cloth while the laptop was on? If so you may have accidentally hit a function key (usually labled Fn) that allows you to use the same key for multiple inputs. For instance while a regular keyboard has things like 5 and % on the same key requiring 'shift' to be held, there may be a 3rd character there that works when the Fn key is enabled.