At one stage I cleaned the insides of our engine , we used a very similar product once , it was branded "Maserati BriteShine Cotton Wadding" - very delicate in the way it removed the carbon deposits.

The only problem was that it contained some sort of silicone which coated the glow plug elements....took about 1/2 litre before it stopped fouling glow plugs.

Now I just use it to polish the outside of my tune pipes.

Brasso & Silvo work well , but be sure to thoroughly rinse off any residue ( wipe with a white paper towel & nitro fuel until clean )