I am waiting on some scarves to return for Paris. I don't know if it has been mentioned but hermes will pleat your scarves (any size, old, new) for a small cost. I always liked the plisse scarves but I never purchased. When the SA suggested it to me as an option to revitalise scarves, I thought it was a good idea and sent in some 90cms.
Like anything that goes to spa, process was the same. Items sent in, examined and quote emailed for approval. Turnaround was quoted 6 months (no different to other items) at cost of 65 USD each (I'm converting from a different currency).
(I don't know if this has already been mentioned by other members so I might be repeating)