We use a fine mesh glass bead to clean rubber and plastic with Vapor Blasting. Our Vapor Blasters have a slurry pump that agitates the water in the cabinet to mix the abrasive and the water. This also primes the mixture into the blasting gun. You use an average of 60 working PSI, starting off about 5″ away and going into 1″ away if necessary. This will clean rubber and plastic, making rubbers like carburetor boots soft. Keep blasting this will loosen up the rubber without hurting it.
Fast Easy Cleaning For Plastic Video https://youtu.be/NmjHAygmIvQ
Restoring carburetor boot, cleaning rubber Video https://youtu.be/Rdr52tSnAFk