Can Shock It Clean remove old stains?
For old, set in stains, pre-treat the area with 2 ounces of Shock It Clean in a 32 ounce spray bottle and fill with water. Saturate the area. Use an extraction type machine over the entire carpet. Vacuum when dry. Keep in mind that some stains can actually damage carpeting. This is especially true if the stain has changed the color of the fabric over time. Remember stains will change the color and once the color has changed and the dye has dissolved out of the fabric the fabric will not go back to its original color. These include bleach, permanent hair dye, old pet stains that have been bleached by sunlight, and wear areas.
