Often we have seen, some tough stains are impossible to go. No rug cleaning service guarantees a complete stain removal service. Yes, an advanced technique of rug cleaning results well on the old and rigid stain. However, there are some substances on the earth that will permanently discolor the rug fibers and material. So, in that case, it is quite difficult to get all the stain eliminated if the rug has very old urine stains, bleach or some permanent inks stain.