What's the best way to remove this??? I have tried alcohol and simple solvents to no
That depends on wether you want to remove just a small area (like eddie mentioned) or the entire board. If you just want to solder a component on a coated copper terminal, a bit of solder flux followed by a normal soldering procedure will do the job for most coatings. If not, heat it with the soldering iron and it will loosen from the copper so you can scrape it off.
If you want to remove all the coating, in general you'll need a specific solvent, from the same manufacturer that provides the coating (one well known is Electrolube). Look for their products in major stores like Digikey, Mouser, etc.
One more simple approach I use (not feasible for bigger boards) is to scrape the coating off with the abrasive side of a kitchen sponge. The downside is that if you have plated surfaces they can be damaged by this.