Cold water, gentle cycle, no bleach, then line dry so they don’t shrink up. Cool iron only, no steam.
Wash them twice a year only, in March and August (it’s not too late for this season), and your hats should last a lifetime.
Better yet, have a ‘Pod Wash Party like we did last week. While the hats were drying, they cooled the patio as well. If you folks have had a ‘Pod Wash recently, post your stories in the comments. (Don’t be shy… just about everybody has at least one tale to tell!)