I have some bad marks on my No 1 exhaust header where my leather key fob was touching and has kind of melted some gunk on to the chrome which has baked itself on well and truly
I have tried a number of solvents but can shift it
I have some pretty aggressive paint stripper I was going to try to see if that softens it but not sure of what effect paint stripper may have on the chrome
Also any other bright ideas