This had better come off!

[GaryTheBadger]

Final update: I think trikermutha was correct...pretty sure it was concrete cutting dust paste. They're widening a road here (for better access to Walmart HQ from the freeway) and that's what I drove through.
It's all gone from my Spyder and I'm a happy camper.

 

[cruisinTX]

hmmmm, OP says it's coming off with water, albeit slowly with a lot of elbow grease. I'm betting it could have simply been wet calaiche or fly ash commonly used in road construction. both are water soluble and will come off with soap and water with the needed effort. However, not being there and seeing it in person makes most; no, ALL of our guessing pure speculation at best.

good luck with it.

 

[Machinegunner]

When I was young, I remember how scary it was to see auto mechanics cleaning parts in a pan of gasoline on the work bench, smoking a cigarette. Most of the mechanics did the same thing. I couldn't believe how stupid they were. Don't remember any getting hurt.

 

[Tazzel]

This looks like lane pavement line paint. If you can remember the location, date and time of where you might have pick this up you can file a claim to the City or Department of Transportation for you State. I have knowledge that they will pay for these types of claims. You must act as quick as possible.

 

[heyharris1]

really sucks, hope you figure it out.

Jim