PURPOSE: To easily remove the glass sticking to the sinterd body which is hard to be removed completely by holding the sinterd body stuck with the glass at the time of hot hydrostatic press at a specified temp. or over under the presence of soln. of alkali hydroxide.

CONSTITUTION: The sintered body is formed by the hot hydrostatic press which sinters the inorg. powder or the pre-molded body of the powder in a state in which the powder or the body is coated with the glass containing 3-15wt.% boric acid at high temp. while applying pressure isotropically by using inert gas as a hydraulic medium, and when removing the glass attached at the time of the hot hydrostatic press, following process is applied. That is, the glass is removed by holding the sinterd body stuck with the glass at above 100°C for 1hr. under the presence of at least 2wt.% soln. of alkali hydroxide. The soln. of potassium hydroxide or sodium hydroxide is preferable as the soln. of alkali hydroxide to be used.