did you test fiber?
after confirming linen fiber, did you disclose warnings to owner?
did you document warning?
did you test for fire retardant?
Did you offer to use a anti browning treatment and explain the pros and cons of it?
You will probably end up having to use a browning treatment and all natural rinse.
Youll need to do a thorough evaluation and be honest.
you might end up having to pay the owner for the current value of the furniture piece or replacement cost for cushions, and a sofa cover
This isn't meant as criticism. I was with everything you said except that last statement. I would never even insinuate that I would be willing to pay for something like this unless I really knew I had caused it. He did not cause this problem, but simply could not with his best efforts solve the problem. When I go into a situation like that I communicate with the customer looking them in the eye and let them understand this may not be cleanable and as such will be a "best I can do" situation. I've been cleaning upholstery since my first year in 1987 and have yet to buy or replace even a single one. I have had a few really close calls though! My very first Haitian cotton chair comes to mind and my first velvet couch and loveseat!!!
All natural fibers stain more easily and often permanently than do the synthetics. Also, you instantly become more limited on how aggressive you can get with your cleaning and especially your stain removal products that can be used on natural fabrics. Hence, your chances of removing certain stains is not good. We don't know for sure what caused these many stains and we have to make judgment calls on what we have on hand that will be safe. My theory is choose only what I KNOW for certain is safe and don't get radical with throwing everything but the kitchen sink at it. If I determined that was either linen or cotton I almost certainly would have been extra cautious about what I used. A simple burn test might have been helpful just to make certain whether or not it's synthetic, natural, or a blend of both. If natural or a blend I clean it the same way. I know going into this I'm trying to save a piece of trashed upholstery and I'm going to try and do it as safely as possible, but absolutely NO GUARRANTEE WHATSOEVER. I place the burden of the decision on the customer. Do they want me to "do the best I can" or do they want to buy another couch or whatever? I love to be able to save stuff and make it look like new, but I would have known going into this it would be very unlikely that anyone could fix this problem. Even simple things like apple juice and other juice drinks can be a nightmare on stuff like this. This could have been dog urine or even saliva from a dog.
If these things are communicated up front clearly and they give you the go ahead I've never had a customer who had any problem although I usually exceed their expectations. There's only so much we can do and miracles aren't one of them.