Hi,
To remove Urine.
Blot up as much as possible if still wet. Apply a Urine Neutraliser and blot. With old stains apply for me a Prochem Fibre & Fabric Rinse or an acidic rinseing agent HOT solution, and exrract. Repeat 2, 3 or even 4 times. Urine stains may cause permanent dye removal and may damage wool or even nylon carpets.
Try to wash this out with a lot of solution even lifting the carpet and first washing out any urine in the under lay let this dry. Then do the same to the carpet from the back then the top pile. Get it Dry as quickly as you can. If at the end of thins you still have a light yellowing apply a Browning Treatment then rinse again
Best of luck.
Bob Jennings