There have been warnings across Thailand since the beginning of this panic-demic about unscrupulous people washing and re-selling masks and gloves (mostly masks tbh).
I’ve seen vendors on the side of the road selling the “gently used” stuff and it’s patently obvious which are the new masks/gloves and which are the used ones.
Best advice (from one who lives in Thailand): if you see a deal on Amazon or Alibaba that is too good to be true, it probably is.
Okay then; I ordered supplies to make medical grade masks, several months ago. I probably should get out my sewing machine and make them.