These are some of my favorite jobs. Coming into a home that has been through severe pet issues and helping them out. These before and after photos were taken while I was removing some pet stains from a Tampa FL home. The best part about these photos is that shows that even though a cleaning might not be perfect it can dramatically change the appearance of a carpet.
Removing pet stains from carpet can be difficult and should be done with the right type of carpet cleaning solution. The reason there is dark spots in the carpet is because of the pet stains and the carpet cleaner that was used to remove the urine. Most over the counter carpet cleaning solutions only compound the pet stain issues in carpet. Spot cleaners can leave sticky residues that attract more soil after the cleaning. That's that case in this particular cleaning. When they used a generic carpet cleaner it left soapy residues in the carpet causing the dark spots that amplified the pet stains.
In most cases you can remove pet stains with water and a clean towel. You can remove over 90% of the urine from a fresh pet stain in the carpet. Flushing it with a few cups of water will dilute the urine and allow you to remove it with a towel. I would also recommend using a few towels to make sure your getting as much out as possible. Then take one last fresh towel and place it on the pet stain and stand on it for a few minutes. That will help squeeze the the urine out of the carpet pad as well.