All 2st Greenish Spark Plug

I'm not sure if this is a fuel, mix oil or mixture thing but I'm getting a greenish color on my spark plug. I've been using Sunoco 110 fuel and Spectro SX mix oil. If I jet it rich it will turn the plug sooty black and on pump gas it was getting cocoa brown but trying to detonate so I switched to Sunoco 110 and tried Spectro SX and now I'm going green but not the environmentally friendly kind . LOL I'm going to switch to VP 110 and Lucas synthetic blend because it's locally available in my new home town so maybe that will change the color to cocoa. Any ideas?

I get the same green tint with Avgas. I think it is from lead.