Abstract: The invention includes a method with the steps of confining a substance which will, upon heating, produce the liquid treating composition and corrosive vapor in a first compartment and confining an article to be treated by the liquid treating composition in a second compartment until both are heated to the designated treating temperature. The treating liquid is then introduced into the compartment containing the article to be treated. In this matter, the corrosive vapors do not come into contact with the article to be treated until the article is immersed in the treating liquid. The apparatus according to the invention includes a unitary structure including a first compartment adapted to contain a substance which will produce the treating liquid upon heating as well as the corrosive vapor simultaneously therewith, and a second compartment adapted to hold the article to be treated and including a means for positioning the article in said second compartment.