I would probably just give them a half hearted hosing down and leave them in the sun a few days. maybe turn them a couple of times so that all surfaces get drenched in a few hours sunlight. Even if you should decide on the laundry route some hosing before and some sunlight after might be beneficial.

From the Smart Pots website:

"After using dump out the soil and let the bag dry. After a few days of being dry, the dust and small roots will easily brush off. For most people, this is good enough. At this point the Smart Pot folds easily for storage. However, a lot of our customers will wash the bags in OxyClean or peroxide to sterilize. They use a washing machine or dip the bag in a tub. Do not put the Bags in a dryer."

https://smartpots.com/faqs/

Hope that helps :)

A ten to one bleach solution should do it,

Thanks for the advice, everyone! Surprised that a simple wash down was recommended. I did a peroxide wash, but don't want to mess around with transmitting disease.