'Cleaning' threads

Never use a tap to clean threads, especially on an aluminum head. There is too great a chance you will start the tap off center and cut new threads. It is very easy to cut new threads in the soft aluminum.

A spark plug thread chaser is what you need. Most good auto parts stores will have them. The thread chaser will clean threads but will not cut new ones.

If you have a Dremel or die grinder, use a small cut off wheel to cut 3 or 4 slots or grooves in an old spark plug along the length of the threads. done properly, it makes an excellent thread chaser.

Keep in mind that you need to use grease or similar material in the slots of the thread chaser to capture the trash the thread chaser cleans out of the threads.

Hey there stranger! Why do you feel you need to clean them up? If the plugs come out fine, I'd simply use some NeverSieze on what you put back in.

If you can turn them in and out by hand there is nothing wrong. I would leave it alone...

I'm with Ray - if you can get them easily started with NeverSieze, I wouldn't worry about it.