A fluid filter is designed primarily--but not exclusively--to filter spent fluids which may contain particulate contaminants. The filter has an assembly which may be slid into or out of a canister housing for manufacture, repair, or replacement. The assembly is a stack of porous filter media separated by perforated metal plates. The metal plates may be arranged in sets, comprising positive and negative electrostatic plates followed by magnetic plates. Or, the metal plates may be arranged in a sequence tailored for the electrical conductivity of a given fluid. A pair of rod electrodes are threaded through holes in the various plates and porous filter media. One rod electrode is connected to all positive plates. The other rod electrode is connected to all negative electrostatic plates.