Caution -- Butane is flammable and dangerous when inhaled. Because of this, it is important to do this fix in a well ventilated space and ensure a complete seal when refilling the Bic lighter.

Identify the small, circular dent in the bottom in the BIC lighter.

Push the push pin's metal tip into this dent until the bead that seals it pops loose. You will be able to hear and feel this.