Oil Pan Storage

[mkmskm]

I have an oil pan that was part an engine I was putting together which I had sandblasted and then painted the outside. The pan was in OK shape but had some pits from rust in the sub pan. At a swap meet I found a much nicer pan that I used on the engine so I have the spare pan with bare metal that I know is going to rust soon. What should I treat this with to store it? I thought about a coat of oil but I figured that wouldn't last and would just attract dirt.