One time I received a cristal from a friend as a gift, I believe is not good it has accumulated his energy and I didn't like that she gave it to me without cleaning it, I have throw it away, but before I want to give it back but she refused.
From what I've experienced. If you're good with using colors with your mind, maybe you could use the color black to absorb the negative energy from it. Then after a few minutes of having the bracelet engulfed in the color black. You could then start to channel white-gold energy in the bracelet to cleanse it. Make sure you're able to move the negative energy once it's absorbed to the side and have it dispersed. Hope this helps.