A Grease-Fitting Cleaner Tool can help those (especially ones with limited hand strength) to open up zerks and other fittings clogged by dirt, sand, old grease, etc., rather than having to replace them. The cylinder-shaped tool consists of a piston that injects a solvent or light oil into the fitting which dissolves the clog as well as lubricates. A connecting hydraulic-pressure hose or gentle hammer tapping provides the injection force (depending on make/model).