Gordon -

I use (believe it or not) Easy-Off oven cleaner to remove the soot and carbon buildup from the stainless steel and mild steel exhaust systems on my (Concours-winning) Cobra and full-scale aircraft... works great. Not sure about Inconel surfaces, but worth trying. I spray it into a container and use a throwaway brush to apply it.

A couple of qualifiers, however:

1. Don't get it on paint unless you try it on a scrap/test sample first...some paint types can be etched or stained.

2. Don't use it on polished metal surfaces (unless you are willing to re-polish with Simichrome or similiar polishing agents).

3. If you use it on aluminum, don't allow it to sit for more than a few minutes or it WILL stain/etch the surface.

4. Wash it off well, I use soap and water or just a water soaked rag.

Barry