Test method for quality evaluation and coated container

A coated container, comprising:

• a container comprising a surface and defining a brimful volume;
• and
• a coating applied to at least part of the surface to form a coated surface, wherein leaching of at least one of one or more types of ions or one or more types of compounds is determined by performing an alkaline treatment on at least part of the coated surface to obtain an alkaline treated surface and performing an acidic treatment on at least part of the alkaline treated surface to obtain an acidic treated surface, wherein the leaching of the at least one of one or more types of ions or one or more types of compounds from the coated surface is 5.00 mg/l or less;
• wherein the alkaline treatment comprises:
• bringing an alkaline solution comprising water and a base at a concentration of 0.0001 mol/l to 1 mol/l and exhibiting a pH of 7< to 14 in contact with the at least part of the coated surface of the container for 1 second to 1 week, wherein a temperature outside the container is set to 20° C. to 200° C. and the alkaline solution fills 10% to 100% of the brimful volume of the container;
• and
• wherein the acidic treatment comprises:
• bringing an acidic solution comprising water and an acid at a concentration of 0.0001 mol/l to 1 mol/l and exhibiting a pH <7 in contact with the at least part of the alkaline treated surface for 1 second to 1 week, wherein a temperature outside the container is set to 20° C. to 200° C. and the acidic solution fills 10% to 100% of the brimful volume of the container;
• wherein the one or more types of ions or one or more types of compounds is selected from the group consisting of alkaline metal ions, alkaline earth metal ions, one or more compounds comprising C, one or more monomers, one or more antioxidants, and combinations thereof.