corrosion on freeze out plug

[Jesse Delanoy]

During this weekend's cruise, I happened to notice a lot of blue-green corrosion on the freeze out plug located on the front of my engine, just below the temperature sending unit. There is no similar corrosion on any of the other freeze out plugs. Is this evidence of serious deterioration of the plug? It's only about a year old. Or is this just minor surface corrosion that can be cleaned off and protected by some anti corrossive goo?

I hope it's the latter - there's not much access to the front end of my A4 - being in a Catalina 30, the front end is almost up against a bulkhead I'd prefer not to have to cut an access panel in.

As always, thanks for the help. I'm starting to get pretty good at some of this stuff, and it's largely due to Don and this site.