Make certain it's a two layer board, or you'll also have to worry about internal layers. A strong light behind circuit board should help in both cases to see how much can be filed down. Also I like using one of those desk mount magnifier lamps when working on delicate circuit boards...you know the lamps with the circular florescent bulb with the magnifying lens in the center. I'd go with (NON-power) hand tools myself. Power tools would be too hard to handle (IMHO). Dremel might jump and break component or trace on PCB, and belt sander is just too strong (again IMHO). If you want to try the power tools, may I suggest you go to your junk box and find an old (broken) circuit board to play with first. Have you worked with or designed PCBs (like I have)? Experience always helps.