Rust on compressor - Cleaning and Prevention

I am setting up an older set of train horns (My 3rd set!) and wanted to know if anyone has addressed the rust on the compressor? I’d like to clean it up, what best to use to clean this up and prevent it in the future? (The container will be ‘portable’ is the plan) Many Thanks

I’m not sure about cleaning, maybe WD40, but you can prevent it by applying “Fluid Film” every 6 months or so, as we recommend with our compressors. Corrosion X makes the same claim but we haven’t tested it.

This helps thank you