I picked up a 16 FZ09 used about a month ago (1200 miles) and the exhaust is dirty/brown. I'm talking the blocky portion that is visible from the left side of the bike beneath the chain/footpeg? I'm wondering if maybe it's burned chain wax from overspray? If it is burned wax, is there a recommended method/product to clean it? If it's not chain wax and is just normal discoloration, I assume there's nothing that can be done? Thanks.