[woofa.express]

Some more worthless information for you.
It doesn’t seem so long ago, but probably 30 years, when aviation fuel (avgas) had a lead component. At a 100hly service it was necessary to remove lead in the upper reach of the ceramic insulating cylinder. One could purchase a special cleaning tool but I used to use a disused hacksaw blade which I had ground down on a bench grinder to a blunt point with a reach of about 1 and quarter inch. This was followed by a clean on a spark plug cleaner. I didn’t put platinum electrode plugs on a cleaner.