Originally Posted by bubbahotep
Any odd metals that might be on the 2 plugs shown are from crap thats on the work bench.
That's good. If it were aluminum, it would be troublesome.
What you don't want to ever see (images below) are extreme examples like these. Detonation and/or lean F/A mixtures are more likely to "pepper" the porcelain w/Al or material from the ground strap- or both, for that matter: