The big thing about vinyl is getting it clean before painting. The shutters should be cleaned with TSP or softscrub first, to remove any oxidation.
Make sure to use a good exterior paint, 2 coats of course. If you are able to spray them, the finish will be smoother. They can also be brushed and rolled. This will put it on thicker but will leave a slight textured look.
If you have cleaned them thoroughly first, you won’t need to use a primer before painting!
Good Luck!
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