How do I clean and refresh a heavy wool wall hanging?

Can you put it in a commercial (large) dryer with no heat? If so, id go that and throw in a couple of dryer sheets.

There are commercial cleaners who specialize in heirloom quality textile cleaning and I would make a lot of phone calls- just to see what I could find.

Wash it gently in a bathtub with Woolite or baby shampoo. Roll it in several bath towels to remove most of the water (DO NOT WRING!) Finally,lay it outside out of the sun to dry completely flat

I would gently clean it in a sink or tub ( depending on it's size ) w/Woolite and warm water. Just fill the sink or tub w/water and mix the Woolite into the water with your hand. Add in your piece.

Woolite leaves a residue that is not good for the textile. Look for ivory soap flakes or a cleaner made specifically for quilts. Do not agitate it in anyway-let it soak a bit, as mentioned above, and then roll in a towel, dry flat and not in the sun...

If this were mine, I would put it in my dryer with no heat for at least an hour or more. Woolite sounds good, but I have had colors run on me. I would check it after an hour to see how much dust has come out onto the filter. I have had to be satisfied with what the dryer can do in a couple of hours. If you do not do this semi-annually, would suggest you do it on a regular basis. Other than that, perhaps you want to find an oriental rug cleaner who will wash and dry it for you. My opinion is they are the safest ones to go to.

That is beautiful. I'm not sure I'd be comfortable washing or even drying it. I might just hang it outside for a bit to refresh it or take it to a dry cleaner or pro to see what they recommend.

Put it in the dryer. Select no heat fluff only and check it after a few minutes. If needed repeat the process.