Tires: discolored spots on outside lugs

[OldRanger]

What are the small blue/gray spots indicative of on these tires? Michelin PS4S, after track day on Summit Main. I’ve seen the scrubbing before…but not the discoloration on the outside lugs.

[elbert]

My guesses:
Blue is oil or overheating of tire
Gray is kitty litter from oil spill or gravel dust from paddock

[OldRanger]

My guesses:
Blue is oil or overheating of tire
Gray is kitty litter from oil spill or gravel dust from paddock

Interesting. There was an engine failure involving a lot of cleanup.

[Estoril]

Interesting. There was an engine failure involving a lot of cleanup.

Its that Turn 1 kitty litter 🙄

Although that was Saturday AM. That should have been long gone.