A regenerable desiccant filter assembly, for use in a vehicle lamp housing, includes a hollow body defining a chamber therein, the hollow body having an inlet and an outlet formed therein to allow air to flow from an area outside said hollow body into and through the hollow body. A substrate, which is a nonwoven fiber mat, is housed within the hollow body; and a regenerable liquid desiccant composition is distributed on the substrate. Preferably, the fibers making up the substrate have hollow internal cavities formed therein, and extended openings formed in the sides thereof in communication with the internal cavities. Preferably, the desiccant composition is an alkali halide or an alkaline earth halide. Most preferably the desiccant composition is selected from the group consisting of lithium chloride, calcium chloride and magnesium chloride. In specific embodiments, the desiccant filter may be combined with a bulb shield or with a bulb socket member. A method of dehydrating air flowing into a ventilation opening in a vehicle lamp housing, using the inventive apparatus, is also disclosed.