How to remove burned in plastic?

That Weber E310 I am just fixing up came with a rotisserie. The bracket mounted to the firebox has some bad "stains". Originally I thought it was burned in grease but closer inspection revealed that whoever mounted that bracket did not remove the scratch protecting plastic wrap. So over time that plastic has slowly melted and burned onto the metal.
Is there an easy way to remove it? Maybe it should try to burn it of completely? E.g. with a torch?

That was the first idea that came to my mind.

Tried to use a torch last night. But most of the plastic was already baked in. But with a wire brush on the drill I got it nice and shiny again.