The cap that comes with our fuel bottles features a child proof “lock”. The child proof caps can be tricky to remove, especially if the bottle has been overly tightened or pressurized by change in elevation. To remove/twist off that childproof cap, here's a a tip/trick: stand bottle vertical on solid surface or ground, take a tent stake or long screwdriver, slide it through the opening, with stake/screwdriver ends jutting out equidistance out each side, and while standing over bottle, place a hand on each side of stake/screwdriver, grip and push down while firmly twisting counter-clockwise.