Sanding will take it down, but there is a good chance the table will be damaged. If it is a small drop, and the table is plastic, lacquered wood, or a similar smooth surface, there is a small chance you can "break" it off of the table, as the epoxy wouldn't have had a good surface to bond to. Aside from that man, you have to be conscious of your surroundings when working with these sorts of products. Always put down cardboard on any surface you don't want to completely screw up (I use a piece of scrap plywood on some saw horses as my workspace). I would highly recommend doing all of your resin work and fiberglassing outside as it is very messy.