Contaminated Needles
1910.1030(d)(2)(vii)
Contaminated needles and other contaminated sharps shall not be bent, recapped, or removed except as noted in paragraphs (d)(2)(vii)(A) and (d)(2)(vii)(B) below. Shearing or breaking of contaminated needles is prohibited.
1910.1030(d)(2)(vii)(A) Contaminated needles and other contaminated sharps shall not be bent, recapped or removed unless the employer can demonstrate that no alternative is feasible or that such action is required by a specific medical or dental procedure.
1910.1030(d)(2)(vii)(B)  Such bending, recapping or needle removal must be accomplished through the use of a mechanical device or a one-handed technique.

All Needles used for tattoo and piercing are "Sharps." 
 
All used tattoo and piercing needles are considered Contaminated Sharps.

All "Contaminated Sharps" must be disposed of immediately after use 
by being placed in puncture-proof sharps containers with closable leak-proof lids.
Conclusion:
All used tattoo and piercing needles are to be disposed of
immediately after use into a sharps hazard container.

Removing or disposing of the needle portion by 
bending, breaking, melting or incineration is directly contrary to OSHA regulations and a violation of safe work practices.
They must be immediately discarded.

You cannot give them away.
You cannot save them for later use on the same customer.
You cannot melt the tips off.
You cannot re-process them. Period.
YOU CANNOT Re-STERILIZE USED NEEDLES.
It is 100% clear and unambiguous: they go into the sharps container. Period.

Because tattoo needles are solid it would be reasonable to expect that they could be re-used after proper cleaning and sterilization.  But NO.
Regulations require  all sharps  to be single use and all contaminated sharps must be discarded immediately after use. into Sharps Containers
Needle List