a ceramic sponge made from plastic is described . because of the ease of cutting the plastic in various shapes before converting to ceramic several unique applications are possible . in case of a column packing better contact between liquid and gas is made . for an auto catalytic converter better contact between gas and catalyst is realized . by cutting in other ways a filter to remove solids is made , permitting longer use before clogging , also a scrubber to remove particulates . a rotary ceramic filter is described ; it is also a composite of fibers and ceramic which retains small particulates without excessive pressure drop upon passage of fluid through the filter . an acid resistant collector plate for an electrostatic precipitation is described .