WIREWOUND POT FIX
I was viewing your posts on antiqueradios.com. I am not a member there, so I will post this suggestion here on CVRS.
I was just about to hang up my skates for the night. When viewing the pics of the damaged Wirewound Pot, I remembered a fix another chap executed on a wirewound pot. As most of the winding on your original Pot is still seemingly in good condition try the following. Nothing to lose!
Cut away that portion of the winding that is damaged, and remove all the burnt area, but only the burnt area. Then scrape clean both ends of remaining winding, Unwind a couple of turns of the smaller part of the original winding and solder the two cut ends together. Making certain that the wiper, when rotated will not bind on the soldered area when operated. Also, using Dioxit clean the complete wiper surface of the remaining winding, and the sliding surface of the wiper itself in case it too is tarnished or burnt. Also prior to soldering, check for continuity to both winding posts on either side of the cut out area. If you take care in doing this I see no reason for this not to work. You may as well read the Ohmage of the newly repaired Winding. It should be fairly close to that of the original winding minus 10 or 15 percent, and still be within tolerance.