Paint question dealing with heater box

[95CobraStang]

Hi-

I just took apart my heater box assembly (which probably hasn't been used for 25 years) to replace everything. The box is in nice shape, but the inside has a little rust on the metal and the entire thing needs to be repainted. Here are two questions:

What kind of paint (spray can) should I use on the box? Does it get hot enough to require anything special?

Should I get rid of the inside rust, and if so, what do I use?

thx

 

[mustangman1974]

mine was fiberglass looking stuff and metal. I sanded it all clean and smooth and used rustoleom primer and all purpose flat black spray paint. I took mine out last year and it look go after 10 years besides the scratches I did to it taking it out.