As some of you might know that the packaging on these flashing teeth toys say that the batteries are non-replaceable. I'm here to tell you that they are wrong.
Step 1: Getting the circuit board out
To start you will need a sharp razor blade knife (please use discretion while using sharp objects suck as razor blades). Next take the knife and make a cut big enough to get the small circuit board out.(see photos 2 and 3 for reference).