I use a LOT of them at the store. About once a month I gather up a large bag of them, load them up into a "lingerie" bag and throw them in the laundry alone with 1/4 cap of regular laundry detergent and wash in hot water. I dry them in the dryer with no fabric softener sheets. (Fabric softeners will make the cloths leave oily streaks.) Been doing this for over 6 years now and some of my microfibers have been used the whole time. Cheaper ones tend to fray and start to unravel after a few washes but good ones last for years this way.

Respectfully asking -- how would you know that the new cloth did not have something detrimental to the coating on your lens when it comes to you straight from the factory in pristine condition? If you can "trust" the manufacturer why would it be so hard to "trust" that you cleaned the cloth and left no detrimental residue? Remember in 2010 McDonald's had to own up to cadmium on children's Shrek cups. I doubt that Ronald McDonald knew that there was cadmium on the cups but it was there.

A more conservative approach might be to clean the cloth when you get it new to remove anything left from the manufacturing process. Or use individually packaged lens wipes from Zeiss or Hoodman Lens Cleanse wet and dry packets and toss when done.