IT would probably not be 100% effective, but Radio Shack used to sell several products designed to help suck-up solder from circuit boards that were being repaired. One was a suction bulb. You melt the solder with a soldering iron, and suck it up into the bulb before it solidifies. The other was a non-flammable wicking type material. I think I would try to get most of it up this way, and then use the moderators knife method for what was left.