How do I remove undercoating?

[CamarosRus]

Dave, I am very frustrated with the cleaning prep process I chose to take
on this 73 Camaro body....I have too many hours (??) in the prep Ive been doing
AFTER the initial Softening Scraping Heating and Pressure Washing of the Dealer
Undercoated areas. I should have taken body to sand blasters which I still may.

While this is going to be a very good quality DRIVER Camaro I still want good adhesion
and appearance of the SPI Epoxy prime on the underside.

I'm told that the SPI Black Epoxy has a semi gloss sheen, so may leave and not top coat
with any further single stage.