No local driveway restore company's near to you friends house, I'd be on the phone to a professional instead of listening to some of the suggestions above
Will petrol not melt the tarmac ?
Yeah it will but only the upper layer.
You can look at the bottom layer then
Petrol will melt the tar and stain it, a power washer will take the worst off but you will end up with stripes where the nozzle was close. A wire brush might be the safest.
It will wear off after a few months!