Rinse the derma roller under hot running water after use. If there is any blood on the derma roller, soak it in warm water with a little washing up liquid added until clean. Be sure to rinse well with water. Sterilize your derma roller by standing it in disinfecting alcohol for at least 20 minutes. After cleaning/sterilizing, place the derma roller on a clean towel until it is dry. Once dry, replace the needle cap and store the roller in a clean place. Whenever possible, try not to let the derma roller's needles come into contact with any hard surface (doing so will make them blunt more quickly). You will know when your derma roller needs replacing; when the needles become blunt you will find it becomes more difficult to push them into your skin.