Someone had spilt glue on the rear leather seat of their Hyundai Santa Fe. That was a problem in itself. But then a solvent thinner was used to try and remove it. The thinner did not remove the glue stain, but it did succeed in removing the leather finish on the surrounding area, along with some of the colour.
There is a simple lesson here: Don't use solvents on leather. Practically all upholstery leather vehicle interiors and most household leather upholstery are pigmented or coloured and then sealed with a clear finish. Using a solvent will weaken the finish and cause colour loss. This is not something that can be solved by cleaning. The only remedy is professional refinishing.
Fortunately, we could reverse the damage for our client, and you can see the results for yourself in the photos below.