You can also vacuum whatever carbon that gets into the pre chamber with a small hose adapted to a vacuum cleaner. I'd imagine that any carbon that's still in the pre chamber won't cause any problems and will get burned up since it's so hot in there. Just make sure you give it a good Italian tuneup afterwards.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked