How do you paint vinyl shutters to make them like new?

They are just screwed on. Remove the shutters. clean, sand and paint.

Remove them, clean and spray paint with rustoleum 2X for vinyl, apply two light coats allowing to dry in-between and seal with a clear UV protectant

I took mine down, washed really well and spray painted them. They have been in place for 4 years and counting still look great. Used Krylon spray paint in black.

removing is always best..but quite a job. I removed mine and spray painted with Rustoleum. Beautiful !

It might be more of a pain, but I would remove and paint so you know they are covered well, and no paint gets on your siding

Thanks for all the suggestions, everyone!