PURPOSE: To separate glass parts effectively by dissolving part of the glass solder, then depressurizing or pressurizing the inside of a picture tube, and allowing cracks to initiate at the sealing part.

CONSTITUTION: To separate a panel 2 from a funnel 4, an electron gun is cut off in the condition that air is introduced into the CRT. Then frit glass 20 is dissolved by nitric acid. A vacuum of several Torrs is provided from the neck 5. In case no destruction is generated at the frit seal part 7, the panel side-face 2B, for ex., is beaten with a hammer. Thus the panel 2 can be separated from the funnel 4 effectively.