They withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments. Art is sometimes etched into glass via the use of acid, caustic, or abrasive substances. The reaction mixture obtained is filtered and extracted with aqueous caustic soda. Potassium was first derived in 1807 by electrolysis of caustic potash (potassium hydroxide). Methyl ethers differ from simple phenols in being less hydrophilic, caustic and poisonous. The diaphragm prevents the reaction of the caustic soda with the chlorine. They are heated and mixed with caustic potash or caustic soda. Imports include petroleum, bunker fuel, fertiliser and caustic soda. Intense cleaning with caustic chemicals is required to get rid of it. The fuel was decladded by boiling it in caustic soda. This is because wool is soluble in caustic soda solutions. A diluted caustic brine leaves the cell. Soap was rare and made in some households from fats and caustic soda. They also wear industrial respirators for protection from caustic vapors. Hubert turns into a black, viscous, and apparently caustic fluid and oozes down the cupboard.