I'm getting good results with the eSun cleaning filament. One advantage it has is that it will melt at a wide range of temps, so I can do initial cleans at 250, but if I wind up with a bit of cleaning filament left in the extruder when I start on other materials, it will also push through down to 220 or lower. It works as advertised IME, and effectively pulls crud out. I can usually see through the nozzle bore after a cold pull.
If you already have white ABS or nylon handy, it may not make sense. If you're sticking to PLA, PETG and the "non stinky" materials, buying the cleaning filament makes sense. YMMV.