Here's a quick way to get rid of the globs of adhesive that remain on the surface of your disc sander after you remove worn out abrasive sheets. Goo Gone (available at hardware stores and home centers) attacks this problem like nobody's business. Goo Gone is citrus based, so it's not as harsh as paint solvents.
Remove the disc sander's table and lower guard or dust shroud. If you can, tilt your
sander so the disc is horizontal. Squirt some Goo Gone on the disc and
let it soak for a few minutes. Then scrub the disc with a small
fine-bristle wire brush. When the adhesive residue is all dissolved,
wipe it off the disc with paper towels. Clean the disc with water to
remove any remaining Goo Gone solution and dry the disc.
Magic American Products, (800) 321-6330 www.googone.com, Goo Gone, 8 fl. oz. bottle, $5.