[Jim]

I have access to hundreds of gallons of contaminated fuel, for the environment and for free fuel, I would love to be able to use it.
Fuel removed from boats/jet skis that had the fill  cap left off and got varying amounts of ocean water mixed in, people tried to use it in cars with bad consequences, any thoughts???

[Babcock_Hall]

First the disclaimer:  I am not an industrial chemist.  What makes you sure that it is the salt and not the water that is causing the problem?

[ATMyller]

Phase separation and continuous liquid liquid extraction. Both methods will separate both salt and water from hydrocarbon partition, but unfortunantely also ethanol if the gasoline had any added.

You can distill the ethanol off from the salt water and add it back to the hydrocarbons or just dump industrial ethanol straight from a bottle if you're feeling lazy.

[1940LaSalle]

Actually, leaving the ethanol out is not necessarily bad.  Ethanol has been known to have a deleterious effect on any number of elastomers in internal combustion fuel systems, especially in older engines or engines that may sit for some time between uses.  I for one would be inclined to forget it, especially if it'll be used in (let's say) recreational marine engines or portable generators.