 How to remove coffee stains from carpet. Grab some paper towel and gently block the stain. Do not scrub. Absorb as much of the liquid as possible before the coffee stain sets in. Flush the area of the carpet with no more than one cup of cool water. With another towel, continue blotting the area. Next, mix two cups of lukewarm water with one fourth cup of lemon juice. Add a bit of liquid, dish washing detergent to the mix as well. If you don't have lemon juice, you can also use one third cup white distilled vinegar to two thirds cup water. Apply the solution with a clean sponge. Don't soak the sponge, but get it damp enough to have an effect when applied to the stain. Begin at the outside of the coffee stain and gently rub in a circular motion, working your way to the inside of the stain. Rinse the area with clean cold water. Using a clean dry towel, remove any excess moisture. If the coffee stain remains, repeat this process until...