How do I remove colored cake icing?
Frosting usually contains butter or shortening, or some mixture of the two; and so you do NOT want to rinse the stain first before treating it. Instead, start by gently scraping away as much stain as you can (plastic knives work well for this) to minimize the amount of stain you need to actually treat. Next, pretreat with liquid dishwashing detergent—a good liquid laundry detergent will also work well—to solubilize (break down) the concentrated butter/oil. To do his, apply a little directly to the stain and rub in. Wait 3-5 minutes and then rinse in warm water.
Now you can launder the item. For white, bleachable items (always avoid bleaching wool, silk, mohair, leather, and spandex) wash in the hottest water recommended on the care label using your favorite detergent and ¾ cup Clorox® Regular Bleach2 (or ½ cup Concentrated Clorox® Regular Bleach). For colored items, wash in the hottest water recommended on the care label using detergent and Clorox2® Stain Fighter and Color Booster. Allow the item to air dry and then check for success. This is important because residual oily stains can be hidden on a wet or damp item, and you’ll want to keep it out of a hot dryer to avoid heat setting a stubborn stain that might otherwise come out with a second treatment.