well, if you actually want to remove the rattlecan AND the factory base/clear, you can chemically strip it with an aircraft stripper type product for fiberglass... it's just a bit milder, your local autobody supply place will have it..
but you are committing at that point to totally removing the finish.. ya just wanna make sure to neutralize after stripping.. and obviously that's only gonna remove 90%, you'll still need to go in and sand some..
or, you can forego stripper, and mechanically remove it with sandpaper from the get go... this allows you to stop at any depth you want.. but be very aware, it is not steel and can cause low spots, etc very easily with sanders, grinders, etc if you are not careful and watching your layers and what your removing from where.....