If you want to make sure your dies will never rust again you need to pick up some Corrosion X.
It was first used by the military in the aviation industry, but is now available to everyone.
Many of us that own/use AK's that shoot corrosive ammo like the AK-74 use this stuff to prevent corrosion from the salt in the primers.
All Corrosion X products are the exact same stuff, just different packaging/applicators.
It works great! Try some out.
P.S. I don't sell it, work for the company, or benefit in any way. I just like to spread the word for a great product!
-Masta