Depends on the plastic/acrylic material.
The brittle ones work best for me with a honed skew with a thin shear/planning cut, and shear cut/scraped final surface.
Softer material such as camo blanks (tend to be very soft in my experience) most any thing can work.
middle of the road -- either rounded carbide or skew
Got problems with a skew -- Try a Keith Tompkins designed skew to get confidence. Really hard to get a catch with it (or to take hogging cuts)