If there is any oil still on it rub some dust on it
But really i have never heard of this one before your tyres must be made differently to ours
Your mechanic is an IDIOT and a scammer!!! The most you have to do is wash off the oil if it hasn't been worn off by now through driving. Road surfaces have a lot of oil on them already because many cars, especially older ones, drip oil all the time. Asphalt is made from oil, so you're driving on oil all the time. Tires are made from oil (and other products like rubber).
The tyre is wrecked you need a new one. Piece of advice - when it comes to something like this ask another mechanic or better yet a bike tyre shop. If the two people who said your mechanic is scamming you were the only ones to answer and you took this as a second opinion and believed it then you would be riding around a death trap. Once the rubber has soaked oil in it can not be removed and that spot on the tyre will never have the grip it is supposed to have again. Also never clean a tyre with gasoline as someone mentioned, this both leaves a slight oil film on the tyre and its no good for the tyre's rubber.
Clean it with a little gasoline then with water & soap, and it will be okay. Be careful when using the gasoline.
Oil can ruin rubber but it takes time. As long as you clean it asap, it will be okay.
Note: Oil can ruin asphalt if there is too much.
Think about it this way, would you rather risk your life and bike over a $150 tire that never hurts to have replaced? I had my rear tire coated in oil but only overnight. Then i used a lot of brake cleaner and a brush to get it out then had to wait while i obtained a new drain plug and oil. After that, i did a quick burnout to burn whatever oil had seeped into the middle, out of there. No problems since but that was only overnight that it sat there. Its up to you. If you want to test the waters, drive carefully and work your way up like youre learning to ride all over again and if it feels fishy, replace it! Im guessing its something like a 120/70zr17? I recommend a Bridgestone Battlax bt-016. Great tire so far! Very confidence inspiring on my 07 Kawi ZX-6R. Got it for $98 shipped from dennis kirk (google it) and installed for $54
I have a 2002 R6 that happend to have the front wheel in a large puddle of oil (long story short) and my mechanic told me i needed the front tire replaced because the oil was absorbed into the tire and was not usable. I just wanted to get a second opinion on this.