The wrong chemicals used can damage your carpet
Chemicals being used that will destroy or permanently stain your carpets, is the most common mistake I see. Sometimes when this happens, the only option maybe a carpet repair!
Domestic, hired carpet cleaning machines are not good! Being injected into rich, wool carpets is a high alkaline shampoo. People use these to break up grease. However, not only do these solutions damage the appearance of wool (fuzzing). But a ph level of 14 can alter the chemical structure. Also, reversing the magnetic charge for dyes to fuse to wool. Therefore, leading to colour bleed or even stripping the colour. Especially carpets constructed from nylon.