The easiest way involves handing him a bucket of hot soapy water and a scrubbing brush.
Easiest for you that is. Give hime time to ponder his actions. :)
Have tried that Doug gave him a bucket of hot soapy water and bleach and a scrubbing brush but it has made no difference there is a fair bit of it think he will be visiting a DIY shop and buying some sort of chemical oil remover
This is something I have used in the past, spread neat washing up liquid on the oil patch leave it for about half an hour and then used a stiff bristled brush to give it a good scrubbing and then swill it off.
Tony it's a lot more than a patch he was changing the oil wasn't watching what he was doing and it overflowed the container and has left a length of oil all the way along the drive grrrrrrr I'm fuming
If all else fails Swarfega make a product called Jizer for degreasing etc costs about £5-£10. The last time I had this problem a good soaking in Jizer then a blast with a pressure washer did the job.