Locate the arrow-like symbol on the metal part of the vial cap.
Using your thumb, push up until you feel the cap pop or snap. Don’t break off the cap just yet.
Securely holding the vial, slowly and carefully peel back the cap until the aluminum is peeled all the way back. The metal should be completely cut through from the top of the revealed rubber lid to the bottom of the lip of the vial. At this point, you may break the cap off or keep it on – your choice.