To save electricity and protect environment, I eschew drying the microfiber cloths in the dryer. When I place them in an open plastic box to dry, dust, lint and motes end up on the microfiber cloth! I don't use a plastic box with a lid because then water will evaporate much more slowly.
Microfiber can be machine dried if you prefer, use a low heat setting and NO FABRIC SOFTENER. Air or line drying is also an option, be sure to do this somewhere the towels cannot be contaminated with dust or lint.
Can I put microfiber cloths in the dryer?
I recommend tumble drying on low, or no heat. You can even air dry them if you want.