Aluminum foil and water...........let it make a little paste......thats aluminum oxide..........wont mar finish and rinses away........l clean up all my chrome that way.......OL wonders where all the tin foil goes....hehehehehee
This is going to sound overly simply, but let the pipes cool and try Mr. Clean Magic Eraser. I had the remains of a rubber boot sole, and melted rain suit on my heat shield. I used Moco cleaner without much success. I used the Magic Eraser and I'm not kidding the stuff came right off. I don't know how it works, but it does.
$1 oven cleaner at the discount store. Don't get it on painted items. Use in ventilated area. Spray on and wipe off. If gunk is being difficult, heat the pipes. It is oven cleaner. And you can't beat the price.