Join Date: Apr 2014
WD-40 is great stuff to use during cleaning and as a. Penetrating oil, but never as a final step for display or storage.
I use it myself, but wipe it off and degrease with acetone or some other suitable solvent.
For long term display or storage, the only way to go is with a hot wax treatment.
I'm in New Orleans and the years ago we had a storm that caused havoc on everything. Since I months metal conservation business I got to see up close all sorts of flooded metalwork.
By far and away, hot wax treated blades held up the best, sometime with no damage. Oil washed away and gave minimal protection.
What I would do is to clean the spots from your blade and hot wax it. Without seeing it, that's about all the advice I can give.