"On the same note, ERSIN made a solder called save-a-bit when soldering irons had a copper tip.
They added copper to the alloy to prevent the erosion of the tip from the normal lead/tin alloy.
I think I remember it as Ersin "Savbit". Incidentally, soldering-iron tips are _still_ made from copper, it is just that they are now given a plating of iron, which prevents the copper from being dissolved by the molten solder (allegedly). Such bits should not be filed to renew the tip, because that removes the protective iron plating. The problem is, we all do it when our bits become pitted, but perhaps such filing is limited to the very end of the bit? I suspect that most common solder used in electronics still contains a little copper.