Partially screw out the piston of the TissuePress to make room for the tissue. Unscrew the brown "cap" and remove the stainless steel wire screen. Place your sample into the cavity of the TissuePress. If the tissue is partially fibrous or covered with membrane, trim out these tough parts and/or precut the sample into small pieces. Connective or fibrous tissue can interfere with the passage of soft tissue through the press.
Generally, the 2 mm array of holes molded into the cap is used. If you chose to use the 500 micron stainless steel wire screen, center it on top of the clear TissuePress cylinder before screwing the brown "cap" onto the clear cylinder section.
Crank down the piston to extrude the tissue. It will exit the press having a paste-like texture. Quit when it becomes difficult to turn the piston or it bottoms out. Do not attempt to use tools to extrude more tissue. It will break the TissuePress. Depending on the content of connective or fibrous material in the tissue, the yield of dispersed tissue will vary from 20-95%.
Clean the TissuePress promptly after use. Unscrew the piston from the cylinder and unscrew the cap. Remove tissue debris and clean all parts with a non-abrasive cleaning solution. Removal of tissue debris from the stainless steel screen can be difficult. An overnight soak of the screen in 1 N NaOH followed by scrubbing will help.