A lot of different spots have a chance of removal. Stains are another story and often are permanent. In essence, almost all spots are organic, and they attract soil like a magnet.
Untreated pet urine left in carpets tends to remove carpet dyes, creating stains that are most likely permanent. Depending on the severity of those stains and the type of carpeted material, natural or synthetic varies in success.
The primary method of stain formation is surface stains, where the staining substance is spilled out onto the surface or material and is trapped in the fibers.
The longer the stain material remains in the carpet, the higher the chance of permanent color change, even if all the original stain material is removed. Check out our Wow! Photos.
Unknown spot by the customer, and a unknown time it's been setting there in the carpets. We think it was soot, and was unsure if it would even come out. Here's the results. You might see a little shadow, but it's far better than before.