Vacuum cleaner filters, in particular replaceable vacuum cleaner filters suitable for both wet and wet/dry type vacuum cleaners are disclosed, as well as vacuum cleaner systems incorporating the use of such filters, and methods for their use. The filters include a filter element arranged in a closed circumferential, cylindrically-shaped path, a top end cap having a central orifice capable of constricting a post on a vacuum filter cage, and optionally a molded end ring oppositely-spaced from the top end cap for engagement with the lower motor housing of a vacuum cleaner.