I've done it heaps of times on old cars and bikes with crappy points ignitions. I think I've still got a little 12V spark plug abrasive blaster in my garage somewhere, you'd just connect it to your bike/car battery, shove the plug's threaded end into a rubber diaphragm, and press the button, and after a few seconds the plug would come out like new.
When I was a poor young soldier I owned an old 6 cylinder Ford with a points ignition that used to occasionally foul the plugs, so I'd whip them out, blast them and put them back in, I had that car for years, and don't remember ever buying new plugs for it. Cheers, Terry.