The experts at About.com provide tips on how to remove purple food coloring, as well as all food-coloring stains, from clothing, like jeans. This entails using a product mixture of oxygen-based bleach and water on tough stains if pre-treatments and regular washing do not work for stain removal.
Mary Marlowe Leverette of About.com suggests first flushing the stain vigorously with cold water. Following the cold water rinse, Leverette says the next step is to apply laundry detergent or pre-treater to the stain. Next, the jeans should be placed into the washer.
Should a stain still be visible, this is when Leverette suggests implementing the mixture of an oxygen-based bleach with cold water. The jeans should be soaked in water with the dispensed amount of oxygen-based bleach per the package directions. Oxygen-based bleaches include OxiClean, Clorox 2, Country Save Bleach, and Purex 2 Color Safe Bleach.
With the oxygen-based bleach method, Leverette says the mixture with water should work, though it may take a few tries before the purple food-coloring stain is fully removed. Food coloring is comprised of dyes that come in liquid, gel, or powdered varieties, and because of the concentrations, the colors stick easily to fabrics.
If the oxygen-based bleach soak method fails after the first try to remove the purple food coloring stains from the jeans, create a new oxygen-based bleach and water solution, and repeat the process. When the stain is removed, the jeans can head to the washing machine.