I never have, haven't had to put them away wet or muddy in a while. Guys used to talk about water a scrub brush and some mild soap or simple green. I've found rain cleans them off pretty well, so setting them up and spraying them good may suffice and is a lot faster than scrubbing each one. I consider dirtier ones juvy colored and don't worry about it.
Nope never waisted my time cleaning them. Sooner are later I end up hunting a rainy day and it helps clean them up. By the time they get so dirty it bothers me. The bags are at the end of their lifespan and time too put new bags on them.
I rarely clean - I have used tire foam with bleach then hosed off with stream nozzle or just used power washer, laid flat on ground, stood on stake and one sweep and clean. Takes two people as my son laid them out, I ran power washer, he picked up and stood up so they dried and threw more out. Took an hour for couple hundred.
I did one time years ago with my starter spread of about 40 dozen that came with short stakes 12-18". I bought them dirty and my last hunt was in a permission field for a weekend and it rained hard covering them with mud. That summer I converted most of them to 24" fiberglass stakes. Since I was taking them apart anyway, I did 35 bags at a time in the washing machine after hand scrubbing most of them. Turned out pretty nice. Since then I might single out a select few to clean that are incredibly dirty but it's a permanent spread so chances are nature will clean them up several times a season.
I bought a bunch of new socks, a bunch that were used and abused by an outfitter. Side by side the used dirty ones looked disgusting but we had to really work at it to tell them apart while picking up. I don't clean but I also don't buy juvie socks lol. Time in the field makes juvies.