<p>We describe here a new electroetching process that enables patterned anisotropic etching of metals without any heavy metal ion salts and demonstrate its self-precipitation functionality for heavy metal ions including cations of iron, nickel, chromium, and manganese to minimize wastewater generation and to prevent heavy metals from flowing into rivers or groundwater. For this purpose, all heavy metal ion salts such as FeSO₄, NiSO₄, Cr₂(SO₄)₃ and chromates were replaced with NaCl, and boric acid was used as a buffer to form alternative electrolyte solutions. The etching pattern was created using acrylic dry film photoresist, which is widely used in industrial-level chemical etching processes. Using this electroetching process, stainless steel plates with thicknesses from 0.2 to 0.5&#xa0;mm were anisotropically etched according to the photoresist pattern without damaging the photoresist. Heavy metal ions released from the metal plates through electroetching immediately reacted with OH⁻ ions generated at the cathode, turned into precipitates, and slowly sank downward. The electrolyte solution containing the precipitates could be used repeatedly without any treatment. The precipitates were filtered out efficiently and quickly, even with an ordinary filter paper, indicating that heavy metal ions do not flow into rivers or groundwater. This electroetching process can offer an attractive option when better product quality is required compared to traditional isotropic etching methods while being environmentally friendly at the same time.</p> Graphical abstract <p></p>