A spray gun (1) has a fluid reservoir (11) which contains a removable liner (13). The liner (13), which may be thermo/vacuum-formed from a plastic material, is a close fit within the interior of the reservoir and collapses as fluid is withdrawn from within the liner during operation of the gun. Preferably, the liner has a comparatively-rigid base and is capable of standing, unsupported, outside the reservoir. The side walls of the liner are preferably thin in comparison to the base and can be collapsed for disposal of the liner. The reservoir (11) has a removable lid (15) and is capable of standing, inverted, on its own so that it can be filled with fluid. The lid (15) also functions to secure the liner (13) in the reservoir and, at the end of a spraying operation, the lid (15) and the liner (13) are removed together from the reservoir (11) and discarded, thereby simplifying the cleaning of the spray gun.