Okay most of the trailer i'm living in has carpet except one bathroom and the kitchen I have a hoover carpet shampooer every time I shampoo the carpet dark spots start to appear after awhile after I clean it and its in the spots where the cats and dogs puked and had some accidents on how do I stop the dark spots? what cleaner do I use? as i'm shampooing it goes away but like 1-2 hrs after the carpet is all dry they re appear BIGGER which is irritating.