At risk of showing my age,
Does anyone remember a company called Rainbow that used to do carpet dying in house for problem stains but also just to change the colour of the carpet.
Quite amazing went on several jobs were they had been called in as well and got to know several of their guys it was clever stuff and they were very skilled , but it just fell away as either, surprise surprise insurers would not pay for it any more and customers no longer had carpets dyed.
Insurers shot themselves in the foot with this one as carpet replacement proved to be far more costly, than a localised re-dye.
It would be quite a lucrative add on to a business today I believe, now that the skills to both dye and retuft have all but become a thing of the past.
(I don't mean Rainbow Restoration by the way different company altogether )