Not certain that reciprocating engines have the same problems as their plugs
are not as shrouded as ours so combustion process probably help keeps
blowing off deposits on the ceramic center cone.

FWIW

Ed A

Ed, The piston engine plug is exposed and the heat range is calculated to allow the deposits to burn off. It does seem obvious but it is amazing how many racers just don't have a handle on hot plugs/cold plugs.
Bill Jepson