It's curious how the FAA changed its advice over the years. They used to say polished frost (which is smooth) is OK to depart with, but now they want it all removed.
I can see why they used to allow a departure with frost if polished to a smooth surface - the average spamcan aerofoil is not going to be that critical if the layer is reasonably even. But personally I would remove it all. A bit of TKS fluid does it OK. I bet polishing the stuff takes just as much elbow grease.