It is not uncommon to come cross urine spots during carpet cleaning around forest Lake area, they could be from cat, dog or toddlers. Many pets find a place of your carpet as their favorite “relief” ground, and repeating wee there, then a visible yellowish stain can be developed. Otherwise, you often can smell them, but can’t see them with your eyes. That is why we always do a pre-inspection with a black light. Urine spots glow eerily under a UV torch. Dog’s urine is a bit yellowish and cat’s is more bluish.
Urine contains many chemical components, and only two of them give out fluorescence (glowing) under a UV light: a phosphorous containing salt and a kind of protein. In carpet cleaning, we try to remove the bulk of urine components to get rid of the unpleasant odor and also for hygiene purpose. We use the UV glowing as a marker to locate the urine, and as an indicator to see how much urine has been removed.
Urine removal is a bit challenging. First of all, urine can penetrate beyond the carpet backbone, the underlying and reach the concrete ground. Therefore, a cosmetic method, like a typical stain removal, would not work. You need a deep flushing method. In Stellar Carpet Cleaning, we saturate the carpet with urine treatment solution, flush it, and extract all the liquid back with a water claw.
Secondly, there are many different components in urine, contributing to colour and ordor. We found it is difficult to remove both ordor and colour with a single step. Proteins can be best removed by enzymes and some organic salts can be degraded by oxidizing agent. It is not a surprise that most of the urine components are very water soluble, then can be easily flushed out if enough water is used. For instance, urea, a compound can release ammonia and make the carpet smelling like the toilet, can be readly washed away with water. However, , uric acid, the main culprit for both urine ordor and yellowish colour, is not very soluble in water and can crystallize deep onto the floor, and may bind to the floor. The uric acid crystal will give out odour once it meets moisture. Simply flushing is not an effective way to remove uric acid. The elimination of uric acid requires enzymes such as urease, which are found an ingredient in many commercial urine removal solutions. In Stellar Carpet Cleaning, we developed a two-step approach to eliminate smell and visible colour.
Thirdly, not all UV-glowing spots are caused by urine and not all urine spots can be detected by a black-light. The rule of thumb is: if urine spots are all over the place or large patches of visible stains, then it is time to consider replacing the carpet, rather than cleaning it.
Finally, it is almost impossible to completely remove the colour: either a visible stain or a UV glowing spot, because you can not 100% recover the flushing water. No matter how many times you try to wet vacuum (dry pass), a large amount of moisture will be left on the carpet, and it contains dissolved chemicals. It takes very little of these urine chemicals to produce a glow. In a recent urine removal, we managed to make the glow much duller. Refer to the “before and after” photos below: