Fyeahbjdmods posted this information a while back, and since it pertains to the question I just got, here it is:
“I really want to mod a female Monster High doll into a male one. Meaning, I’d like to get rid of the breasts. How is this done? Do you use sandpaper…? I’m not really familiar with this kind of plastic and mod work.”
“Yes, it’s very possible to sand down MH breasts. xD There are several issues I have come across, though:
Monster Highs are hollow. If you sand too much, you get holes (not that I’ve accidentally that nope, not at all, there are absolutely no gaping holes in the chest of my WIP Cleo noooope…. u__u).
However because of this, it’s kind of hard to get a perfectly flat chest or make it look like they have pecs. But then again I guess MHs aren’t ones for total anatomical correctness, so the biggest issue you’d have is the hollow part.
Also something that can help is if you slice off the breasts with an exacto knife or dremel attachment (oh my god I can’t stress how important it is that if you try this, please be careful!), just only about halfway, and then finish it off with some sanding
Unlike resin, this MH plastic is much hardier and would take infinitely longer to sand them down if you used only sandpaper.
Also, use a high grit when sanding. You can get a bumpy surface that’s really difficult to smooth out if you start out with a low grit paper.”