My wash mitts....over time, they just don't feel supply soft...

Just for the helluva it, I put my wash mitts on fairly hot water from the pot, did a MF wash in the washer and even threw it in the dryer which I rarely do with the mitts....I generally just put them on the gritguard and they are dry by the next wash session.

Is it shampoo/buildup in the MF that I'm not not realizing. Granted the MF mitts are pretty -soft- once wet, it just have that nice fluffy softness when dry these days.