Do I have to mask off areas like glass or chrome trim like sand blasting requires?
Hardly ever. In fact, unlike the abrasive property of sand, bicarbonate-of-soda does not harm window glass or the rubber seals around the glass. However, it may be harmful to certain types of plastic trim, because you are using 150+ pounds of pressure in some instances. For this reason, you may want to remove or protect those possible areas. Other areas that may need protection are: wood, soft plastic, membranes and electric components.
