When people ask this, we think there may be an assumption that we are re-using needles. This is not the case at all. For the last 15-20 years, acupuncturists have used one-time use, sterilized, disposable needles as the industry standard. So there is no re-using of needles even from one part of the body to another.
Sterile package opened, needle in, needle out and put into a bio-hazard box to dispose of responsibly and that's it.