For some reason, the brass brush didn't occur to me before. I'll have to get one to keep handy.
I use a brass tube cut at a slant to scrape off the burnt residue. Like the video shows, always go in the right direction, so you don't catch the edge of the thin chrome plating. This is also the reason I wipe the tip in the brass wool, not jab it. Well, that, plus jabbing/twisting doesn't do anything. So I disagree with the Ersa vid about the brass wool. Removing the residue from the tip is a lot like removing dried glue from a knife.... the fastest and easiest way to do that is to carefully plane/scrape it off with another knife. On the solder iron tip, you want to avoid even the tiniest scratches, though, because the chrome plating is so thin. This is why a brass tube has been doing the job for me. For many years, no damage.
The tip rejuvinator seems to work amazingly well. I'll have to get some of that too.
I have long been proponent of using mild abrasive over chemical cleaners. The Weller vid shows the "polishing bar" as the first option over the tip cleaner/tinner compound. I agree. If the tip is dying, you have to remove the oxidized/contaminated iron. And there's plenty of good iron underneath. If you clean it with ammonium chloride, you are re-contaminating it. The chloride/halide embeds in iron. This is why you can't clean rust off of your tools with HCl, no matter how dilute (well, you can, but it will flash rust again). But acetic or phosphoric acid are great at this (but they promote a different kind of oxide; abrasion is the best way on a solder iron tip). If you use a fine abrasive on the tip, you just have to keep away from the chrome.
Funny the number of people who think polishing doesn't remove metal. Half the world has read the bullshit description of some namebrand polish and believe it reverses the metal oxide and turns it back into the base metal.