Can't be done - they're ruined.
How To Get Scorch Marks Off White Pants?
I watched this on this old house believe it or not. A trained seamstress for restoring textiles can cut out the burnt part and literally weave in the new patch so you can not even tell where the damage was done. Now that said it may be cheaper to just buy a new pair. This lady was a restorer for a carpet company that restores those high priced area rugs for the rich and famous(museum quality pieces) and it wasn't cheap or a quick process.she would literally weave each thread into place and tie it off from the inside. It was very interesting to see the patch when it was done you could not even tell where the damage was afterwards.just thought I would throw that out there.
You will not be able to get them off. The only thing is to put something decorative over the burn if it is in an appropriate place.
