[Paraphrased from a related question]
Can you tell me when and if I should wash the microfiber applicators?
Thanks for your question. When you clean a record, all the dirt and contamination is swept away by the applicator, and it winds up on the applicator surface. You can clean this dirt off of the applicators.
The applicators, when needed, can first be soaked in a mildly soapy solution (I use few drops of dish washing soap mixed into clean tap water in a shallow bowl). Let them soak a couple of minutes.
Pick a pair of applicators and gently rub them face-to-face to loosen and dislodge soil.
Rinse under lightly running water.
Blot with clean lint free toweling, and let them air dry. Once dry, they can be fluffed (again rub them face to face) and then reused.
Applicators only need to be washed when they look obviously dirty. It’s hard to say how often that will be, given the wide range of record conditions.