MF's all together. Usually delicate cycle like the directions on them say. If they are very covered in product, I usually pretreat them by spraying with Simple Green and soaking them in hot water (sink) with Shout Oxy Power, then proceed to the delicate washing cycle with detergent.
My nasty rags I usually do all together on a heavy cycle with the extra rinse. Ones with a lot of product or gunk, pre-spray with Simple Green. I put a good amount of Shout OxyPower in there as well.
The normally soiled towels and rags, I just do heavy wash with a lil extra detergent and some Shout OxyPower.
These all seem to work for me. I never dry my wash mitts in the dryer.
Good Luck and hope everyones techniques help!