Cleaning Oil Off Rear Tyre.

IMHO - Just scrub the tyre with soap, washing up liquid, etc and hot water. Rinse and repeat, until it dries off looking uncontaminated. If you can get a nail brush or such all the better

 

If you can get any, a good strong solution of traffic film remover will do the job. Don't be tempted to use white spirit or any solvent cleaners. I certainly would not consider changing the tyre!

 

@BT81 Agree with the hot soapy water.

 

Find some dirt and do a burnout in it.

 

YES STRONG SOAP WATER.....hopefully the rubber is not impregnated.....if it is....well???????

 

I know one of the other responders has advised against using solvents but I’d use brake cleaner which is what I’ve used to get the odd splash of chain lube off of the tyre with no apparent detriment.

 

I wouldn't worry about it, the oil won't damage the tyre, you've already ridden 300 miles on it. As long as the majority of the oil has been wiped off, then enjoy the ride.
You could ride through oil on the road at any time but after a short distance it will have wiped off the tyre.

 

I have used brake cleaner too. I did not use it on a large portion of the tire. I was doing a track day when the F3 sprung a leak. If hot water and a good dish detergent had been available. Soap and water would be better.

 

Plenty of soap and water is likely enough. Use something with plenty of dispersant such as dish washing liquid. Once it's dry and there's no longer any sign of oil, ride it like a new tire for the first 100 miles or so.