When the soldering iron is used for a period of time, an oxide film will be formed on the blade surface of the soldering iron tip and its surroundings, which will make it difficult to "eat tin". At this time, the oxide film can be removed and re-plated with solder.

When replacing the soldering iron core, be careful not to connect the leads incorrectly, because the electric soldering iron has three terminals, one of which is grounded, and the other two are connected to the two leads of the soldering iron core (these two terminals are directly connected to the 220 through the power cord. connected to a volt AC power supply). If the 220-volt AC power cord is wrongly connected to the binding post of the ground wire, the electric soldering iron shell will be charged, and it will also be charged when being welded, so that an electric shock accident will occur.