Cleaning and painting recessed cast iron convector/radiator

curlygodmother

I have these recessed cast iron convector/radiator and they are looking rather dingy. Is it ok to paint these? Should I strip the paint off before repainting? How do I clean these?

Asking because I am a total noob and I have searched everywhere and could not find a lot of information about this type of convector/radiator. I have attached a couple of pics. These might be American Standard Sunrad convector/radiators. Or at least they looked like the one from a heating museum article -- https://heatinghelp.com/heating-museum/american-standard-radiators-and-convectors/

Thank you!