I have an incontinent dog and she has urinated on the same area so many times that my Hoover steam machine no longer will get the yellowing out of the carpet, even with going over it many times. There is no odour, just the yellowing stain. I have used many products (that worked when it first happened) like pink solution etc. But now I need some expert help. The stains seem to have set themselves in the carpet because of repeated peeings.