I prefer the Cut-Off Wheel on my moto-tool, over grinders, files, etc. It will take material off quickly, efficiently, but you always need to remember that it is a power tool, and it works amazingly fast, so care must always be exercised.
I found that grinding bits just got clogged up with metal, making them paper-weights. The Cut-Off Wheels can be moved perpendicular to the spinning wheels with gentle pressure, without breaking. I find them awesome for taking off mold ridges on bases, for taking excess metal off of bases as a whole. Here is one I have on file, for when my Harbor Freight moto-tool fails: Handstar with 180 accessories.
At one point, I used a Cut-Off Wheel to remove an entire, molded plastic base, leaving just the two feet of the figure. I then mounted that to my own, thinner base. It worked, but it did take quite a while. I chose a different path with the remaining 30+ figures I was working on. LOL! Cheers!