Al can be done as well...get the local scrap yard and buy a piece of 6061 Al, drill out a hole large enough to slip over the bb axel, then shape the piece with a hacksaw until it fits inside the ruined spline area, weld and lube as directed.
You can also weld a long piece to the part in the bb to use as a lever.
If all else fails, get a BIG hammer and beat the bb spindle off the fused cup, then get a file and create a slot in the remaining desplined cup being careful not to file into the shell of the frame. Once the cup is slotted, catch the outside edges with a pair of channel locks and squeeze the cup so the threads disengage the frame and pull it out. Go the the LBS and have them run a bb tap through the frame to clean up any boogers.
Lot of work, but a valuable experience and puts a little more emotional attachment into the frame