A couple days ago, Damon Campbell posted regarding using Varathane to
protect brushed aluminum surfaces.

At that time I posted a response saying I thought it had been
discontinued. Well, looks like I was wrong. It's a now a Rust-o-leum
product (I guess Flecto got bought). Of course, they don't seem to have
it stocked at the Home Depot I visit like they used to...

There are several types of Varathane. Oil based and water based. I've
only used water based. Great stuff. I might have to check out the oil
based for some outdoor wood furniture I have.