A friend’s cat peed on her expensive genuine down comforter. She fears it cannot be cleaned without ruining the down feathers (liquid cleaner causing them to bunch up). Is there hope to clean it & maintain its quality?
I’m pretty sure you can dry clean a down comforter, although you don’t want to do it too often.
Ah - this is some manufacturer or something, but there’s some pretty good info on this site. Here’s some of the good info:
It may very well be that there’s no hope for anything a cat has peed on, so your friend shouldn’t get their hopes up too much…
Having said that, you can wash down in the washing machine. It’s perfectly fine for down to get wet; ask a goose! 
However, it may not be fine to dry clean down.
Lesson: Expensive furniture and cats do not go well together. 
I would suggest using cold water (perhaps very dilute ammonia, but, as with any organic stain, DO NOT USE HOT WATER) to get out the worst of the smell/staining - if that fails, professional cleaning is probably indicated.
I’ve washed down comforters many times and the feathers never bunched up. Well, they do when the comforter is still wet but when it dries, you just fluff it up and it’s back to normal.
If she is going to wash it, she might try making a solution of 1/2 water, 1/2 white vinegar. Put in a spray bottle and spray the stain. Let evaporate and the smell is gone. (May take a couple of times.) I have rescued several comforters this way and the smell was completely removed.
What you need for ANY sort of cat urine stain (or similar sorts of bodily fluids/solids that pet owners and parents are so familiar with) is an enzyme-based cleaner. My favorite is “Outright”, but you’ll find several similar ones at your neighborhood pet store.
The enzymes break down the organic material causing the odor/stain, whereas detergents really won’t do the job.
I don’t know about cat-pee, but I did have a friend’s chihuahua pee on my very expensive down comforter one day… on the advice of the comforter company’s website, I rushed it right down to a laudromat and had them treat the spot with stain remover and wash it (cold water, gentle cycle) and dry it (medium cool) in large commercial machines. Evidently, home washing machines and dryers are too small and will tend to damage the comforter. They said home dryers will scorch the comforter, as there’s not enough room for it to really tumble and fluff it back up, and it develops hot spots.
A few weeks later, my own dog got sick and peed on it, too. Straight back to the laundromat. The comforter is good as new. They said the trick to keeping the feathers from clumping was to toss a can or two of tennis balls into the dryer with it, to bounce around and fluff the feathers.
In my experience, cats come and go…but cat piss is forever.
I have had exellent results with Nature’s Miracle. Saturate the affected area (they sell it in a gallon size if need be) and then wash with an appropriate down cleaner, such as Down Wash from Nikwax.
Toss a clean tennis ball in the drier with the comforter and it wont clump.