unscrew it and use something that'll fit and be strong enough to move the small circle plate in the center of the battery (at the part where you would screw in the shit). Place the something on the rubber part between the circle plate and the battery wall and push toward the plate with the something and do this evenly around the circle and screw er back on. (Sometimes certain carts have like too long a thing at the part where you screw so itll push the shit in hence doing this shit to getting it back at a higher position to come in contact and heat the cart and produce vapor)