Meth cleans the plugs real well and makes them harder to read to some extent

 

All ive ever run is pure gas or >10% ethanol gas. And mine were green. Ill throw some new ones in my truck and see what they look like after runnin a few tanks of 100% gas.

 

I used to run E85 most of the time and haven't seen green on my plugs.

 

Back in the day when I ran nitrous on the 5.3, I had yellowish/green straps and was told it was the sulfur in the auto-grade nitrous. Didn't have it before using nitrous and was before E10 was prevalent.

I recently changed out the TR6's in the truck. Several were whiteish/grey and #2 had gotten hot enough to burn off the ground strap but none were green. This was on E10 only.

 

yea the bimmer i worked on only ran pump gas

 

Green is ethanol content not burning properly. It's the same stuff you'll find in a carb bowl that E10 evaporated out of over time.

 

By "not burning properly" do you mean overly rich?

 

Either overly rich or just not getting lit off for some reason. Ethanol that is burning properly turns the ceramic blood red at the tip and generally doesn't leave other deposits behind.