Spots on my hood
 

So my truck was in the shop this past winter for a little while and I did not get a chance to give it a good wash and there was alot of salt from the road on it. When it came out there was a bunch of small spots on the hood and top of the cab that kinda look like rust spots. I have tried waxing but it will not take it off. Any one have any ideas of how to fix this