I live near the Gulf Coast with high humidity. We have mild winters, but condensation during storage is a problem. Temps can drop to the high 30s to low 40s then be in the 80s a couple days later. The garage acts like an icebox. Cold metal parts starts to "sweat" (condensation) when the temperature changes hotter same as a cold drink out of the refrigerator on a hot day.

One of my co-workers has a 66 Vette with an L-88 427 (aluminum heads, intake and chrome valve covers). I asked him how he has kept his engine look new after 10 years. He said that when he does engine washes he sprays WD-40 when wet on everything, blows the motor off with a leaf blower and goes on a short drive. I asked about oxidation. During the winter, he sprays W-40 on all aluminum and chrome parts in the engine bay and undercarriage. It soaks in the porous aluminum and prevents oxidation. A couple days later, he wipes off the excess. He also doesn't do engine washes during the winter. The normal oil film on the engine/transmission/undercarriage is your friend against oxidation during winter.

Prior to his advice, I used glass cleaner on chrome parts. Now, I only use W-40 on a rag. It cleans better and protects.