Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Thanks for your replies.

I just cleaned my spark plug using a pipe cleaner and Easy- Off oven cleaner. It really seems to have worked.
After using the pipe cleaner as an applicator, I let the cleaner sit for a while. Then I scrubbed with the pipe cleaner.
The soot came off, bare metal was revealed. I then washed with dish soap. After  rinsing I immersed the plug in meths. I dried the plug and reinstalled. The engine is running fine as I write this.

Paul