Drug and Cosmetic Grade Dyes can be used in Bath Salts & Lotions . They are not water soluble.
These dyes can be added as a colorant to Dead Sea Salts and lotions. The will not dissolve. They are dispersed in suspension in lotions & coat the outer surface of the bath salts. Recommended usage in bath salts is 1 gram for 2 pounds of bath salts. Sprinkle the dye onto the salts and stir well to disperse. Then spray on your fragrance oil to bring the colors to life.