Had a rug like that last week.Sprayed with browning prescription,left for ten mins.rinsed with fib and fab.Spray hot enzall,rinse with f+f Note cleaning may release urine smell.IF smell and colour remain, spray with hydrogen peroxide leave for 15 mines .Rinse with very weak alkaline rug cleaner.If after drying rug still smells spray with urine neutralizer. Pete