How to Clean a Spark Plug?

Learning how to clean a spark plug is a must for car owners who wish to maintain and fix their own cars. | Source:

Oil on spark plug threads is not something you should ignore because it could impair the functionality of your spark plugs over time. You may need to replace your spark plugs soon or clean them to make sure your car stays in good driving condition. Here’s a quick guide on how to clean a spark plug:

Step 1: Remove the spark plugs using a ratchet wrench and spark plug socket.

• Put together the ratchet and spark plug socket. An extension may be required to properly attach the spark plug to the socket.
• Label each wire and its matching hole with masking tape to avoid mixing them up.

Step 2: Clean the spark plug.

A. Using sandpaper
• Using a 180 (or higher) grit sandpaper, gently sand the spark plug to get rid of any debris. Be sure to sand the arm, electrode, and insulator properly.
• Use an air hose to blow off the sanded areas.

B. Using a quick drying liquid
• Wipe off visible dirt from the spark plug using a clean rag.
• Use a wire brush to remove remaining deposits.
• Choose which among (1) mineral spirit, (2) 90 percent alcohol, or (3) carburetor/injector cleaner to clean the firing end of the spark plug with. Make sure to wear gloves and eye protection when applying cleaner on the spark plug. Dry well and use an air hose to blow off any excess dirt.

C. Grit blasting
• Grit blasing is the most effective way to clean a spark plug. Simply attach the spark plug to the rubber seal of the grit chamber and it will do the cleaning.

Check your car manual for spark plug gap specifications. Source:


Step 3: Gap the spark plug.

• Depending on your car, you may need to gap the spark plugs after cleaning. Refer to your car manual for specifications.
• Use a spark plug gauge (gapper) and carefully insert it in between the arm and electrode. Adjust it accordingly to its proper measurement.

Step 4: Reinstall the spark plug.

• Ensure that the threads of the spark plug are clean before putting them back into the holes. Tighten them to the correct torque and double check the wiring if it’s placed correctly.

Still having trouble starting your car? It could be a sign that you need new spark plugs. Here are some high-quality replacement spark plugs from JC Whitney to choose from:

Author: JC Whitney

JC Whitney is the largest and oldest catalog and Internet direct-to-consumer auto parts and accessories retailer in America. Since 1915, JC Whitney has been filling the needs of customers by providing the right part at the best price. You can always shop with confidence at

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