I've spilled worse stuff than that on boards; I have successfully doused boards in 91% isopropyl alcohol, 2 or 3 times, and then let sit for a few hours in front of a fan. I'm not sure what is meant by clumping, but you do want to remove heatsinks/waterblocks that are mounted with a non-permanent thermal interface material, as the isopropyl will dissolve stuff like ceramique or arctic silver.