This question was submitted from E.S.E.
“How do I remove HUMAN URINE SMELL from upholstery?”
Urine removal can be a very tricky business from absorbent materials such as carpet and upholstery. I have seen many carpets & upholstered pieces, that have become urine contaminated, cause the occupant much grief in their attempts in trying to rid the area of the offensive odor.
Urine contains salts that act as a desiccant. That is to say, it can attract and hold moisture better than most materials. If you pass a moisture meter over a urine infected area, even if it has been left to dry for months, you will find that the area where there is urine will have a much higher moisture content in relationship to the surrounding unaffected area.
This is the reason urine odor is stronger when the humidity in the air is elevated (rain outside, shower running etc). This ability to attract and retain high moisture in fabric creates ideal conditions for bacterial, viral and mould growths. Removing urine salts from your living area is strongly recommended from health and indoor air quality perspectives.
Try these techniques :
If the upholstery is of covered with a non-absorbent material cleaning it with household cleaners should readily take care of the problem.
If the upholstery is of covered with an absorbent material with a non-absorbent barrier between the exterior fabric and the foam than having the upholstery professionally cleaned or steam cleaning the upholstery yourself should take care of the problem.
If there is no barrier between the fabric and the foam, than the urine would have saturated beyond the surface fabric into the foam. Surface cleaning the exterior fabric will not remove the salts in the foam.
As an example, if this were carpet we would be pulling the carpet back, treating the back of the carpet, replacing the under pad and treating the sub-floor, as well as clean the face of the carpet. If the urine contamination has gone past the face fibres of the carpet into the carpet back and under pad, cleaning the carpet fibres will not solve the problem. Applying deodorants to the carpet face will only add a scent to the odor but will not eliminate it.
Unless there is a way for you to remove the urine infected materials from inside the upholstery and thoroughly cleaning the inside structure of the upholstery I would suggest you throw it away and get a new one.