The solder we use is actually shaped like a straw. It has flux on the inside that helps remove impurities.
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Probably the most important thing you can do when soldering is to take care of the soldering iron tip. If you take care of the iron maybe some day in your old age it will realize all you have done for it and come visit once in a while. A well cared for tip will at least make your solder joints look good.
Perfecting your technique