Iron temperature melts the glossy paper printed ink listed here and has become transferred to your copper plate. Rub the copper facet of PCB applying metal wool or abrasive spongy scrubs. This removes the best oxide layer of copper and also the Picture resists layer. But while statistics like they're https://electronic-components67653.getblogs.net/67563751/not-known-factual-statements-about-dm-20d