Nearly all iron tips available now are iron-plated. The Sav-a-bit copper-loaded solder only worked with solid-copper, non-plated tips by having the solder already slightly saturated with copper so that it had less of a tendency to leach copper from the tip.
The tip about not wiping the iron before putting it in the holder is a maxim that's lauded by Pace, Inc., considered by many (NASA, U.S. military, etc.)to be the "gods" of soldering and PCB rework.
I don't have a problem of dipping the tip into flux, although there isn't much point if solder isn't involved. The little 1" tin mentioned is "Tip Tinner Cleaner TTC 1" made by Multicore and manufactured in England! This is a 15 gram container and is a mixture of flux and powdered solder and works really well for restoring bad tips.
Don't ever touch an iron-plated tip with any abrasives (files, sandpaper, Scotchbrite pads, whatever) ... soldering joints puts enough wear on them anyway. The iron plating keeps the copper from being dissolved by the molten solder, but once there's a void in the iron, the tip gets eaten up even faster than if it were solid copper since the copper is a more active metal than the iron. It's a bit like the old tin-plated iron roofing. Worked great for stopping rust until a small hole developed in the tin, in which case, it rusted even faster than if it were not plated at all because of galvanic action. That's why they switched to galvanized roofing.
On the other hand, a solid-copper tip or an iron-plated tip that has the iron worn through is a good candidate for dressing up with a fine-tooth mill file. Be sure to immediately tin the iron after fresh copper is exposed.
Dean