In settings where grease has been walked into the carpet I'd use shockwave.Peter, what would you normally use on a carpet contaminated with oil? That may be the answer. It’s lots of work however.
On a lighter note have you offered the customer a peg for their nose
I've used mpower with great success on dog smells on fitted carepts before.
I think the problem in this case has been the depth of the soils in the backing of the rug
I considered the peg option but apparently it wasn't a good look for his wife.