I started working on it yesterday by stripping the Clay Bazooka of its paint by the use of a file then smoothing the surface by wet sanding with a 1000 grit sandpaper. After which I washed it with water and a sponge. After drying I applied some plastic primer then after that I painted the colors that were initially on it.
So far so good. Today I also started disassembling the Rick Dias and working on the main body. For now I was able to start work on one of the legs.
I did a scratch test on the Clay Bazooka and the paint doesn't come off anymore. Lesson learned, I'm not going to do anymore model kit builds without first applying some primer coat.
Next step of this build can be found here.