Portable vocal booth from VocalBoothToGo.com can be easily washed in a regular washer.
to wash the Blanket part of the booth – take it out form the outer Nylon case ( unzip two zippers and unhook two hooks),
then pull out the hard parts Support rods and Support arches.
and throw it in a washing machine!
Dry on a high heat tumble dry.
Drying might take a while because thick cotton absorbs a lot of water.
but after the wash the booth will come out thicker and fluffier than before!

I think that Vocal Booths from Vocal Booths to go are the only mobile sound booths that can be washed.
in this video we show how the Carry -on vocal booth 3.0, a VOMO prototype actually , was washed after about 20 000 miles on the road, with working in all kinds of environment. after it got wet when i was filming Voice over int he ocean. ( i guess the whole reason they do voice over so they do NOT have to record in the ocean ).