Restoring a walk in

My walk in works great but the inside is speckled with rust. It is off right now during a renovation so I figure now is the best time to address it. CLR is not doing a great job. Should I paint it? White box it with FRP? Dry ice clean it? Is there some simple solution I don’t know about?

I’ve never done this in a walk in, but vinegar is good for removing rust, though it usually need to soak on the object for 10-20 mins to be effective. Maybe try to work in sections and figure out a way to attach vinegar solution soaked towels to the surface, then go back and scrub it away.
When the rust is gone and it’s completely dry, I’d seal w paint. FRP is going to leave enough space that condensation would collect and rust will eat at the walls beneath it.
There’s also a product called Evapo-rust that may be useful.
But also maybe contact your fridge tech and see if they have any recommendations

I would consider replacing the box with a brand new one. I’t almost certainly going to be better insulated than your current one and save on electricity use and wear and tear on the refrigeration parts.

Whatever you do, be sure to discuss this with your food safety inspector before you do anything! Paneling the walls will only hide the problem and ultimately make things worse, painting almost never cuts it and if you use the wrong type of paint your inspector will “have kittens”! We encounter this problem quite frequently and many inspectors just want you to clean the surfaces (get the rust off) and just leave it that way so it’ll be accessible and easy to clean again in the future. At least if you follow their advice you will be on their good side now and in the future.
Tom Lehmann/The Dough Doctor