Visible Stain Detection Powders should only be used indoors, subject to the statements regarding their use in the discussion above. A visible stain powder should be selected based on its natural color blending with the color of the target object. It should be carefully dusted on the object with a soft applicator brush. When contact with the object is made, a transfer occurs. When the transferred powder contacts moisture, such as perspiration, facial fluids or water, the powder goes into solution and a resulting vivid color appears.