Abstract: An apparatus and method for continuously supplying and recycling machining liquid in an EDM device employ a filter between a liquid reservoir and a machining location at which the liquid is used. In one embodiment of the invention a buffer reservoir is provided between the filter and the machining location, while in another embodiment a second filter is connected in parallel with the first-mentioned filter. In either case, an assured alternative supply of filtered liquid is provided while the filter is repeatedly stopped and started in response to one or more operating parameters representing a degree of filter clogging. The stopping of the partially-clogged filter unexpectedly permits self-regeneration of the filter without the need for dismounting or backflushing for cleaning; even though cleaning is not performed, the repeated stopping by itself extends the useful life of the filter.