Toss in the wash with cold water. Air dry. Boom.
Not Like They Used to be
"I bought 2 pair of Rothy’s at a store in Arizona about 5 years ago and I loved them. Finally I needed a new pair so I ordered them recently. My old shoes were a size nine so I ordered a size 9. The new ones are about a half size too big. Also the inner sole is now a cheap cardboard replacement to the soft fabric inner sole that was so nice on the old ones. They’ve cheapened the shoe and still charge a lot for it. I will never buy them again!"