Found this clip on website I was led to by a google search...
"...I wanted the ethanol out. I could distill it but I came up with an easier way.
Wash it out.
I get say 20L of E 10 as we have here, throw in say 5L of water and give it a shake. Water and eth goes to the bottom and good, clean pure Petrol to the top.
Takes only a few minutes to separate but I usually leave for an hour or overnight for good measure.
I decant the petrol, not to carefully as I add the dregs to the next batch and repeat.
Water and Petrol DON’t Mix but water and Ethanol love one another."
The site owner goes on to reply this:
"As for the use in gasoline engines, this may be ok in extremely low compression engines on old equipment, but we may need an octane booster after we strip the Ethanol away. My understanding is one of the few advantages of ethanol is it does raise the octane of the mix a bit.. so removing it means you likely have a lower octane Petrol fuel, and may see destructive pre detonation. WE need beware of how we might improve the octane (if necessary) with after market additives as it might contain more alcohol."