... residue left on the heating wire.Just do it,you will find your atomizer is become a new ... perfect. Clean detail:when you have enjoy it for 2-3days,is time to clean.if there is black residue ... shipping we turn off the battery to protect it.when you get it,you should click 5 times within 2 seconds ... ,all the steps have done battery start working.if you turn off it,click 5 times again. Kit content: 2pcs ...