I think the only prudent thing to do here is place the motherboard in the dishwasher. but instead of putting in dishsoap pour several ounce of paint thinner or mineral spirits . . . . better yet gasoline in the dishwasher, then run it through a full cycle. now once it's done, you have to get it fired up before any residue of remaining paint gets a chance to dry on the motherboard, so take it straight from the dishwasher (DON'T DRY IT OFF) and fire it up.
I'm pretty sure that should work. let us know.
