I had not heard of this before, either, so looked it up too.
All foam body.
Must be some soft cover fabric. Chenille, perhaps.
My suggestion to clean is- NO Truck Mount!!
Too much pressure, flow and vac.
I suggest a portable with 50 to a max of 100 psi, a portable spotter sounds about right.
Either that or a furniture bonnet system.
Use a neutral pH cleaner- no high alkaline or acidic cleaning products.
Towel off as a last step.
Charge them PLENTY!!
Gary