This is what I recommend,both in wipe on or spray on.
Boeing developed it to protect metal surfaces on airplanes that have very,very tight tolerances that can't be painted.
I use it on my Galvanized gas tanks on all my Antique cars.
It's incredibly durable and won't harm anything.It's a clear better then wax coating that wears off over a very long time,just re-apply by spraying on a clean rag..

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Collecting Vintage Sunoco