I was researching leather cleaning for my sofa and chair and I found products that will remove deep stains like mustard (a dye like curry) and they also have UV and other treatments and a protector that seals the leather so things like curry can't penetrate. They also have spot cleaning clothes that are pretreated with cleaner. This is the product recommended by the furniture manufacturer and it has a good rep. Name of product is Leater Master. Link is http://www.leathercaremaster.com. I hope this solves your problem. Let us know the outcome so we can all benefit from your experience.

 

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