I'm taking an engine apart and the combustion chambers/valves and pistons are a bit sooted up. I've got most of the carbon/soot/whatever off with petrol and a toothbrush. There's still some stubborn stuff there still, anything I can use to shift it?

autosol and a polishing buff in a dremell type tool?

Just googled imaged it, sounds good

Fine wet and dry paper with paraffine and a bit of elbow grease also works well.

Cheers

Fred W B

For a lazier method, spray the bits with WD40, repeat a few times, it does soften the carbon deposits, making removal easier.

Worked well for me on some bike pistons and valves.

Another vote for Solvol Autosol - I've done loads of bike engines like that. The shinier the finish the less 'sticky' it will be for the carbon.

Just back from town, got some autosol, just the ticket! thanks

Gasket stripper will lift carbon quickly but don't leave it on pistons for too long. Less effort than Autosol as well.

rotary wire brush in the drill type thing.
Valves in the drill and emery cloth
Wood chisel to scrap the pistons.

Is gasket stripper the same as paint stripper? I looked on ebay for some and some of them are shown as "paint and gasket stripper"