A two-part liquid product, the first of which comprises a first solvent and a first dissolved dye; and the second of which comprises a second solvent and a second dissolved dye. The two solvents are immiscible. The first dye is insoluble in the second solvent, and the second dye is insoluble in the first solvent. Each dye is a different color than the other. Initially, when placed in a single container, the two parts form two separate different colored layers that do not mix. Shaking the container produces a temporary micro-emulsion. The emulsion has a new color representing the combination of the colors of the two component layers. This combination color indicates to the user that an emulsion exists and that the product is effective. The component materials are selected so as to produce a stable emulsion for between five to twenty minutes before separation.