Undercoating Removal

Based on what I've read online, it seems that to stop future rusting, the best course of action is to remove this old undercoating that is flaking off and re-spray a liquid coating that won't trap moisture. I live in the PNW, and below is an image of the undercoating, but I don't know exactly what type it is or what the best course of action would be to remove it. Please give me any advice you have. - Also, I have gotten some of it by just chipping it with a screwdriver just to see if it was covering super penetrating rust.

 

^Looks like Ziebart or similar. Some dealership rubberized undercoating has similar properties as well. The coating gums up wire wheels and sanding discs. Best method of removal is dry ice blasting, though it's expensive (I've seen $1400 being mentioned).