Clean the roller:
Wash thoroughly your dermaroller unit, with water and soap. Brush away any residual debris after using it. 
Then soak about 5-8 minutes with 90% alcohol, or use ultraviolet to disinfect for about 45 minutes.
You can also use a cold sterilizer like Clorexhidine solution. Do not use chlorine, autoclaves, steam
and high temperature sterilization methods.

Needle Length:
There are 10 kinds of needle length arranges from 0.5mm to 1.5mm. Different needle length is for different purpose.
Choosing a right needle length for your treatment is the most important point when you buy it.

Cautions:
1) Do not share the unit with other people
2) Do not roll too much more than indicated time. If skin shows hypersensitive response, consult with your doctor.
3) Keep the micro needle part always clean and dry
4) Store in a safe place out of the reach of children