Our carpet is 5 yrs old and we planned to replace it-not in great condition from previous owners. But, since we adopted Kiwi last year it is worse. We finally bought a carpet cleaner for our own use. It helped. But the spots would come back up. (We have bought and tried almost every type of cleaner that exist) Now Kiwi is 1 year old and is doing better but still has accidents upstairs. A friend told me to wet the urine spot and pour Borax on it-let it sit a day or two until it is hard and lift the clump up.
This has been wonderful-the hard clump literally turns yellow in spots where it has soaked up the urine and you can smell it. I then spray a vinegar and water mixture on it. I have had to do some spots twice. But she said if you start off with this the spots will not come back-so far it looks good. When Kiwi is finally trained-we will replace the carpet or put down hardwood floors upstairs. But for now . . . .
PS-any ideas on how to train a Yorkie to ask out when she is upstairs? She ask out when she is downstairs but upstairs, if the moment hits her she squats.