iFixIt microfibre cloth cleaning, How (and When)?

(This is my first time posting to this forum so please be gentle.)

How does one clean iFixIt's own Microfiber Cleaning Cloths? I am anticipating they will get dirty over time, but am uncertain when or how to clean them. I nominally use them with iFixIt's own Screen Saver (which, despite the name, can be used on more than screens).

At the moment, I propose to use Marius Fabre's liquid black soap in warm (not hot!) water. This works great with Silk and other delicate materials, so seems like it could work Ok when the time comes.