This video shows you how the Bissell Little Green Spot remover being used to clean dog stains in carpet. I clean carpets for a living in Tampa FL and I have recommend these little machines for extracting fresh dog stains in your carpet. Instead of using the store bought solutions I recommend not using the sprayer at all. It does not get out deeper spots because the sprayer does not have enough PSI to penetrate the spots or the carpet.
I recommend pouring a cup of water (8oz) on the spots and then using the Little Green Spot Remover to extract the moisture out. It works great without having to use soapy solutions that are only going to attract more dirt after it has dried.
If the dog stains are heavy and have a bad smell to them this machine is not going to be effective at removing them. It's my recommendation to have a professional carpet cleaner come out and take care of heavy dog urine stains.