Open up the enclosed sandblasting area. Most models have a lift-off door or shield that can be easily removed using a screwdriver or a safety latch.
Vacuum out the inside using a dust buster or another hand vacuum. Bring in the vacuum through the door and suck up any loose pieces inside.
Wet a rag with alcohol or an industrial cleaner. Wipe down the inside of the cabinet and loosen any particles.
Place a small amount of Gum Out into a spray bottle. Spray down the inside of the cabinet and let the material sit for five minutes before wiping it off.
Use a hose with a nozzle-end to spray off the blasting area. Point it at particularly dirty areas.
Wet the rag again with hot water. Run it over the entirety of the cabinet.
Use a piece of sandpaper to break up any last stuck pieces. Sweep out the entire cabinet with a hand broom.