Thread: Protection for bare Aluminium Bottom Metal

Seeking advice please.
My M70 Win has PT&G one piece bottom metal of bare aluminium. It could be left as is but I'm thinking over time there is some possibility of oxidation / corrosion occurring. I don't know if I'm right or wrong about this. I'm looking for a very durable, cost-effective coating to protect the metal. I've looked at and ruled out cerracoat due to potential chipping and buildup. The bottom metal has a very snug fit into the stock inlet which I would rather not have to open to fit coated bottom metal. What other options are available ? One suggestion already is just aerosol spraying with polyurethane. I suspect this might be too thin and wear through in time but I am not knowledgeable enough to know. Is this in fact good advice or am I better looking at other ( superior ) treatments ?
Thanks for any advice offered. Cheers.