Can Old Spark Plugs be Cleaned?

Technically, yes, you can clean spark plugs, however, in most cases it's not worth it. We do not recommend it for a number of reasons.

Ultimately, you won't get the same performance from a cleaned plug as from a new plug. Electricity discharges best from sharp edges. A used plug will have worn edges, and cleaning may contribute to the wearing.

If you insist on trying to clean anyways, the cleaning procedure below was supplied to us by an old motorhead:

• Brush off the plug and firing tip with a clean rag.
• Spray the firing end with a quick-dry cleaner such as fuel injector cleaner or brake cleaner. Let sit 10 minutes.
  
• Use a wire brush to clean off any deposits that have loosened.
• Blow off the plug and firing end with an air compressor or can of compressed.
• Re-gap to your vehicles specifications.
• If the plug has a flat seat, remember to use a fresh gasket, or adjust the installation torque accordingly.
  

NOTE: Insufficient cleaning of a spark plug may lead to its failure in a very short period of time. Clean the spark plug thoroughly to avoid problems later. Remember, if a plug is fouling, its usually a result of engine side factors or incorrect heat range selection. If, after cleaning, a plug shows unusual signs of wear or doesn't come clean, its time to replace it.