I also wash my towels in the washer. But like most, I keep them seperate. Polish in one pile wax in another pile, etc. I wash my Microfiber towels alone according to product. Window towels get washed seperate from wax removal and QD towels.
I have an old kitchen cabinet in my garage with seperate places for each pile.
As for the foam, terry, and MF appliciators, I like to wash them by hand. I have a gallon soap container with the top cut off, and I usually soak them in a good mix of dish washing liquid, and wash them by hand. If I fine them really saturated with wax or Klasse, I dump in 6 oz. of Isopropyl alcohol to help break down the wax or sealant. I rinse very throughly, and air dry. I guess once you get them pretty clean by hand, you can pop them in the washer.
We they start to show signs of age, I use them to apply 303, or do my tires, or even cut them in quarters and use the small pieces to do my trim.
When I get rid of them, they are really done! Let us know what worked for you. Enjoy!