Oh, I thought you were physically masking out skin tones and fire and such.
Selective color is something that I use quite heavily in the Jakku grade, but even with fine control and selecting only certain hues at certain saturation/luminance levels it’s still really difficult to find settings that knock out the hues of the sand while leaving all of the skin tones and explosions, or at least enough to not look weird. In the end, I found that taking out all the color in the sand shadows would always play havoc with the skin tones, which is why I settled for settings that targeted mostly highlights and high midtones.