To remove grass stains, wet the stain with rubbing alcohol. Let the stain dry. Now wet it with cold water. Pour liquid clothes detergent over the stain. Fold the stain over itself and rub together. Rinse with cold water. Let the stain dry again. Now let the stain soak in a mixture of water and enzyme cleaner. After a few hours, wash in hot water with clothes detergent.
The next tim you are shopping, if you see the product Oxyclean, buy a few bottles. This is an amazing stain remover and takes out just about everything. If you have some Oxyclean at home, use that instead of the clothes detergent when rubbing the stain on itself.
