My advice to you, is to tell you what I practice, DoNot use a wire wheel, simply flake off the loose rust/paint. Then Use a product called Rust Converter. It is available at any auto parts store. It is cheap. Pour it in a bowl and brush it on liberaly. It will resemble milk. Once it is dry, it turns black. depending on the rust, you might have to do 2 coats. After that, you can paint or leave it be. Use only "Rust Converter"
My frige in the trailer I sold was from 1984, before that trailer, I had one from 1976.
Hi temp paint is not necessary if you decide to paint it, just make sure you let the rust converter dry over night at least