Synthrapol Detergent is a very concentrated and sudsy detergent. It is used to wash out loose dye after the fabric is dyed. Synthrapol helps keep dyes from staining other areas of the fabric. Using Synthrapol is the best way to ensure that your colors stay pure during wash out, and that your white areas remain relatively white. One 16 ounce bottle of Synthrapol can wash from 8 to 24 wash loads.