I have tossed them and I have kept some. I bought some cheap black ones that were all mossy so I just tossed the plant and bag at the end of the growing season. I bought some nice Bloem brand bags that I have used for a few years and they are still holding up. I hand washed them and air dried the better ones. I don’t think I would save the cheap ones. They don’t hold up well.

I don't see myself dumping the potting mix out, washing them and drying them. I did that once - soaked all them in bleach/sodium percarb. Then took the pressure washer and washed both sides as they lay flat.

I think it's a couple factors causing the moss

Medium Broken Down

Maybe wicking from below

-maybe once moss as set into the fabric, (natural fibers, https://rootpouch.com/products/black) . If one does not use any -chems- to kill the moss, as much scraping clean the sides as I do, it will just keep on coming back