Call me paranoid, but I worry about the grindings getting down into my engine. How do you keep it clean? Even if I stuff a rag in the block openings, debris will get on and in the chain and sproket.

Any ideas??

You put a magnet in the grinder spark path.......

That will surely help, but the grinder material disentigrates (sp?) as well.

Vac cleaner [ ON] hose in same path as you grind .
Oil soaked rag around magnet ..