Rainbow® Presoak Powdered DetergentI am convinced that, around 1997, car wash owners started spreading the word about these Rainbow products because sales started growing steady through now. This Presoak Powdered Detergent is a premium high foaming detergent. Sure, it produces yellow, lemon scented foam, but it's also a solvent based formula that will not separate or fall out at high concentrations. We designed this detergent and the complete line of Rainbow products with one goal in