That patina is Cosmoline rust preventing grease. Wash it off, and those tools will be as new.
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The best way to remove cosmo is gasoline-soaked rags, which was SOP back in the day. In these more cautious days, a less flammable solvent.
Removal or not is actually a subject of great debate in the WWII collecting community. Purists refrain, and it can affect value, depending on personal preference. I have cleaned a few tools, and I have kept others caked in cosmo and cheesecloth, on a case by case basis, often depending on the other tools and the purpose of the display.
A NOS on-board toolkit such as the Dodge WC above (all Vlchek, btw, except for the heavy duty integral handle screwdriver, which is an IRWIN, and the spark plug wrench, which was supplied by Dodge but almost certainly contracted out), wouldn't be issued to and stowed on the vehicle in that long-term storage condition, so it would be inappropriate for a WC at a show or parade all geared up for action. Used tools would be better. It might look good displayed with a mint condition factory class truck, no unit markings, no pioneer kit, etc, as if it hadn't been shipped out yet. That would be cool.
If it was mine, I wouldn't touch it.