Abstract: Pasty materials are mechanically dried by passing them through a pressing zone established between conjugate elements for subjecting the material to be treated to the action of pressure in direct contact with the free surface of a layer of open and communicating cell foam which serves as a sponge and is supported by its surface opposite to said free surface against a wall for the application of pressure in such a manner that the spongy layer becomes impregnated in the said pressing zone with liquid previously contained in the said material to be treated. The liquid is caused to pass right through the spongy layer up to its opposite surface while filtering through the open communicating cells. It then issues from the supporting wall -- which is porous to this end -- so as to be finally evacuated.