Personally, I would save the WD-40 for in the garage. I wouldn't dare get it anywhere near my cameras. It might not be corrosive, but I would think that it would make the outer casing (Whatever it may be: Leather, Vinyl, plastic, rubber, cowhide, wood etc. etc.) oily. I do agree with the Stainless Steel wipes.
When I decide to put a camera away for a couple months, I usually do a deep cleaning of everything, and put it in one of my bags with Sillica.
My thoughts, take it or leave it!
My weapons consist of 11 cameras. And counting... Be afraid.
We are the makers of music, The dreamers of dreams.
WD-40 will peel the leather from the camera body.It will migrate under the edges and dissolve the adhesive. As Anscojohn states, use silicon. There are silicon impregnated cloths that are designed for wiping down metal and removing fingerprints and other corrosive materials that would eat into the metal finish. I dont think I would use an aerosol spray, as the solvents in it will do the same as WD-40 to the leather.
I would also add that silicon should be used carefully too - it will make the body rather slippery in my experience which may not be the desired effect...CRASH...oh sh*t there goes my £2000 Leica onto the concrete...!
Just a note that silicon damages lens coatings. For my collection, I use a little leather dressing on real leather, wipe the metal with a Windex dampened cloth and clean lenses with a good lens cleaner and tissue. I don't use the cleaner if it's only dust. Keep my cameras in a display case in the living room. Some of the shutters get sticky from disuse, but they all look good. My Grandmothers 1917 Kodak Autographic still looks and works perfectly, and that's the oldest one. Just the way I do it - your mileage may vary.
Moma don't take my Kodachrome away!
Oops, Kodak just did!
Even if you're lucky and silicon doesn't damage the lens coating, it's still a complete nightmare to remove as it's designed to be ultra slippery so everything slips off it including lens cleaning fluid.
I read somewhere that lighter fluid (Ronsonol or Swan brand etc.) is a good general purpose camera cleaner (NOT for lenses) - does anyone else use lighter fluid...?