I came across a distinctly black liquid shoe polish stain on a wool carpet. This had already been tampered with by a number of proprietary solutions but to no avail.
It is always more difficult to tackle a difficult stain that has been unsuccessfully treated with a variety of cleaners already. The chemical composition of the stain is altered from the original problem.
Undeterred however I proceeded to gradually remove the black stain with a variety of our powerfully effective solvent cleaners. The result was fairly spectacular and the client who had previously planned on an insurance claim instead decided to have the whole carpet cleaned.
Our business can be really satisfying at times.