Many, many moons ago someone painted the grille on my '69 a goldish color. They also had gold stripes on the car, so I imagine it was proper auto paint (Enamel? Lacquer? Your guess is as good as mine).

Not as many moons ago, I painted that same grille black with the same ChromaSystem paint I was using on the rest of the car.

Go figure, zero surface prep + years of spray car wash wax + no primer... the new paint is peeling off.

What's the proper way to strip the grille down and start over the right way? My initial thought was to soak it in brake fluid, but that'd be a lot of brake fluid and I'd hate for it to soak into the plastic and cause more problems later.

I would have conserns about using anything that might soften or melt the plastic. I have had good luck using EASY Off oven cleaner (yellow can)It is time consuming but does not ruin the plastic. I have used it on the interior parts of my 68 Chevelle, the previous owner painted everything with base coat clear coat. Good luck