Abstract: An ink jet cartridge is refilled by establishing a fill opening extending from an outer portion of the cartridge into an interior ink bladder of the cartridge, applying pressure to sides of the cartridge to provide a decreased volume of the interior ink bladder, transferring ink into the interior ink bladder through the fill opening while maintaining the decreased volume, sealing the fill opening, and relieving pressure on the sides of the cartridge to provide an increased volume of the interior ink bladder. The fill opening can be established using a poker. Transferring ink can include using a squeeze bottle filled with ink. Pressure can be applied to the sides of the cartridge with a clamp similar to a #100 binder clip manufactured by Office Mate International Corporation of Edison, N.J. The fill opening can be sealed with a set screw or a ball cork along with pressure-sensitive tape.