I don't think your pot is ruined. I buy a few each year and restore them. If it sits level and is not cracked, it is restorable.
With your pot, I would put it on the outdoor grill for a couple of hours, let it cool, remove the resulting carbon with steel wool and water, and reseason. Put it on the cold grill, and let it cool without opening the grill. There is a risk of warping or cracking if it is heated or cooled too quickly.
The cleaning cycle of the oven will also work, but the fumes will vent into the house.
I would stay away from blasting or sanding. Both remove too much metal and there is the risk of driving the offending residue into the pores. Too aggressive use will result in a rough surface.
If that should fail, then there is the lye tank. That is a 5 gallon bucket full of lye water. Also an outdoors job. I cover the pail with a piece of plywood weighted with a concrete block to keep the critters out. Read the instructions on the lye container. Lye goes into the water slowly, not the other way around. Put the pot in the tank and forget for a week or so. Longer does not hurt. Rinse well and you are ready to reseason.