I have some new plugs that were pitch black after about 30 miles of driving due to a carb that was in need of adjustment. I adjusted the carb, cleaned the plugs with an abrasive spark plug cleaner and ran the motor another 20 miles. Now the plugs look clean and the motor is running better, but not as smooth as it should. Is it possible to ruin the by either running so rich that they are al black or by the plug cleaner? Maybe both?

I have never reused or cleaned a plug for over 30 yrs...
The old plugs of the 40s 50s 60s where built crude and solid...modern plugs are hi tech items...from the ceramics to the terminals and elecrodes.
Drop a plug or box of plugs just pick it up and throw it in the bin. Hence one reason I have old carpet under the engine .....this also soaks up any oil spills lol
To establish correct heat, the center elecrode should show about .5 mm at the tip of heat blueing of the metal.. if tou have sooting you have an issue with nixtures and/or timing curve, engine wear and stuff like that.
Cleaning with abrasives kills the sharp enger of the elecrodes...the spark jumps from these sharp edges...in the old days one cleaned the plug then refiled the electodes...same with dizzy rotor and pins.
Once one has the correct heat range (run as cold as possible and maybe a hotter plug on the cnrs) one can still get a little bit of sooting around town, but hit the highwaym SLOWLY increase speed and rpms over 5 or 6 miles cleans the plugs off...
If one plants the foot, hi temps cause any desposits to glaze on the plugs...
This can be seen ...on a trip after about 50/70 miles the car seems to start to hum along very nice...this is when the glazing has finally burnt off....increasing rpms slow reduces this distance to near nil.

I have never reused or cleaned a plug for over 30 yrs...
The old plugs of the 40s 50s 60s where built crude and solid...modern plugs are hi tech items...from the ceramics to the terminals and elecrodes.
Drop a plug or box of plugs just pick it up and throw it in the bin. Hence one reason I have old carpet under the engine .....this also soaks up any oil spills lol
To establish correct heat, the center elecrode should show about .5 mm at the tip of heat blueing of the metal.. if tou have sooting you have an issue with nixtures and/or timing curve, engine wear and stuff like that.
Cleaning with abrasives kills the sharp enger of the elecrodes...the spark jumps from these sharp edges...in the old days one cleaned the plug then refiled the electodes...same with dizzy rotor and pins.
Once one has the correct heat range (run as cold as possible and maybe a hotter plug on the cnrs) one can still get a little bit of sooting around town, but hit the highwaym SLOWLY increase speed and rpms over 5 or 6 miles cleans the plugs off...
If one plants the foot, hi temps cause any desposits to glaze on the plugs...
This can be seen ...on a trip after about 50/70 miles the car seems to start to hum along very nice...this is when the glazing has finally burnt off....increasing rpms slow reduces this distance to near nil.
X2 do not clean plugs with abrasives.

I'll try some new plugs tomorrow and see what happens...