OEM Wheel as Spare a bad idea?

I bought a second set of wheels for my snow tires, but I'm thinking I might just get a set of 3 peak AT tires and not deal with the swap anymore. That leaves with a set of wheels to find a use for.

I was thinking I might save two for a future trailer and then use the other two for spares. Would putting an aluminum wheel under the bed as a spare be bad? It should be no worse than when it's being used to drive, but maybe being just sitting there getting gunked up would be bad somehow. At least with a matching spare and tire I would be able to rotate the spare around.

 

Just mount it with the good-side up so it doesn’t get gravel-washed and it will be fine. Lighter weight than the steely! Might gain 1/20th of an MPG!

 

I did the same getting upsized Duratracs, but I sold off my Kevlar Highway tires while they were still fairly new for $600. But I had no future plans for them. I kept the OEM steelie under the truck, as we get a lot of snow & salt here.