Back in the day I used my cheap $10 iron during a carpet installation to poke holes through the carpet for the seat belt bolts. This obviously left a bunch of melted crap all over the tip. I took it over to my bench grinder and just ran the wire wheel on it until it was clean. It cleaned it alright but it took the shiny coating off the tip and it never really worked like it should again. From that point on, the solder would just ball up and fall away from the iron instead of flowing over the tip like you want it. I just saved the tip for carpet installations or whatnot and bought a new tip that I use strictly for electrical soldering.
