All too often when I am called out to a customers house to clean carpets I am faced with carpets that have white patches all over them due to the customer trying to remove stains using shop bought stain cleaners.Most stain removers even the big name ones from the High Street do more harm than good.If you are intent on using one it is best to dampen out the whole area of carpet first not just the stain.This MAY help to reduce the risk of patches.