How We Treat Urine Stains
So today's job was to clean and deodorise a carpet with a urine stain. The smell of urine can be particularly obnoxious and very difficult to remove and sometimes impossible to remove the yellow stain completely. This is because urine contains ammonia. Ammonia is used to fix dyes in dying processes. In years gone by, Harris Tweed used to be soaked in sheep or human urine. This helps to soften the fabric, but also it sets the dye, particularly indigo apparently. As urine dries, it turns into uric crystals. Embarrassingly, if you were wearing a Harris Tweed jacket and it started to rain, the uric crystals would dissolve, releasing an overwhelming smell of urine and everyone would move away.
So the main problem with a urine stain is that it usually soaks right through the carpet pile through to the backing and the underlay. Standard carpet cleaning processes, if done professionally, will only clean to the base of the pile as it is not good practice to over wet a carpet when cleaning. Certainly wetting the backing is not a good thing as the carpet will take too long to dry and there is a risk of shrinking and if the carpet takes a 24hrs to dry (it should only take 2-4 hours) then there is a very good chance that the carpet will start to smell musty even after it has dried. If it has a hessian or jute backing, this may well wick up through the carpet pile causing browning.