I'd just continue riding like normal it will wear away. maybe if it feels safe do a few hard roll ons just to speed it up.

 

Do a burnout.

 

You can use a little kerosene to clean it off if you're really worried about it. Follow up with some warm water and dish soap after that. Since it's in the middle of the tire you don't have to get your panties in a twist. It's not like you'll be losing corner grip.

I'd carefully remove any solid pieces out of the tread and call it a day. Friction will remove the rest on your next ride.

 

Ye got tar on yur tar. What's the problum?

 

id prefer the rolling burnout

 

+1

at least you'll have a nice repaved road now