How to Remove a Cast Iron Clean Out Plug

Cast iron clean out plugs are found in older homes to aid in removing clogs and other obstructions in the plumbing system. However, if your plumbing system is in good repair, you may find that you rarely have to remove it. Over time the cast iron plug may rust, making it very difficult to remove. In this case, there are a few things you can try to make the job a bit easier. Once you've gotten the plug out once, make a note to unscrew the plug twice a year. This will help prevent any problems with the cast iron clean out plug sticking in the future.

Step 1: Coat the seam between the plug and the rest of the plumbing with a penetrating lubricant such as WD-40. Allow 30 minutes to elapse before proceeding to the next step to allow the lubricant to work its way into the seam.

Step 2: If you see any visible rust along the plug and the plumbing, scrub it away using a wire brush. Reapply penetrating lubricant if you have to do any scrubbing and wait 30 minutes. If you don't see any rust, skip this step and proceed.

Step 3: Use an adjustable pipe wrench to firmly grasp the peg at the end of the cast iron clean out plug.

Step 4: Give the pipe wrench a good pull, trying to turn it counterclockwise. If you can't turn it with your bare hands, use a mallet to hit the end of the adjustable wrench and therefore turning the clean out plug.

TIP: If a couple of hits don't yield any movement, reapply the penetrating lubricant and wait 30 minutes before attempting to try again.

Step 5: Once the wrench has begun to turn, continue turning it until you have completely removed the clean out plug. After the plug has been removed, conduct any plumbing repairs.

Step 6: Clean the threads of both the cast iron plug and the pipe it screws into with the wire brush. Coat the threads of the cast iron plug with penetrating lubricant. Screw the plug into place, giving it a couple of turns with the adjustable pipe wrench to ensure it is secure.