Chloride ions are widely present, such as salt/sweat/seawater/sea breeze/soil. Stainless steel in the presence of chloride ions, corrosion is very fast, even more than ordinary low carbon steel. Therefore, there is a requirement for the use environment of stainless steel, and it is necessary to wipe frequently to remove dust and keep it clean and dry. (This would give him an "inappropriate use.") There is an example in the United States: a company uses an oak container to hold a solution containing chloride ions that has been used for nearly a hundred years and is scheduled to be replaced in the 1990s. Because the oak material is not modern enough, the container leaks due to corrosion after 16 days of replacement with stainless steel.