"Cleaning" spark plugs without some sort of bead blaster to get the abrasive up into the area where the porcelain insulator meets the steel plug shell accomplishes one of two results- - - -"Slim" and "None". At least that's been my experience for 65+ years. Go ahead and try if it makes you feel better.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!