I just cleaned mine very well with soap and water several times. Wiped the panel down with plastic safe paint prep cleaner. But i used spray dyes, I did one at the beginning of the summer and left it outside just t see how it would adhere. it still looks like the day i painted it. If you are going to use paint, there is a product you can buy for plastics to enhance paint adherence so you can use most any paint. I think paint is too thick looking though. The thing that kills ya when painting interior parts is silicone. Like armorall, you need to make sure it’s very clean.

Is it not sticking or are you getting fish eye? Little spots where the paint like craters?