I usually clean my bases with base cleaner and it works fine. But it appears the grime is getting pretty deep into the base, the cleaner isn't getting it out. I guess hot scraping is the way to get it out now, but I have some questions....
By "hot", does that mean still liquid. Like, make a pass with the iron then immediately scrape? Or does it just mean you don't wait 30 minutes after coating it, just scrape when you finish applying it.