Best way to separate pinch welds

I bought 5 spotweld cutter bits from Eastwood years ago, still have 3 as I miss-placed the first 2.

I center punch the weld then drill through both pannels with a 3/16 bit. Then drill out the bad side. I have no problem rewelding the small hole using a thin copper backing block.

I have also used my plasma cutter on welds that I can get the head on to. A quick blip and the weld is gone.