Yes you can. WD-40 is an excellent preservative and drying agent. It always comes out very well in corrosion tests. It is not the best lubricant, but I assume you don't want the outside all that slick anyway. If sprayed on heavy and allowed to dry - and not talking a day here, more like weeks - it will form a gummy residue. So will most light oils. But, it is a solvent for itself, and if you spray and wipe off you will have no problems.
What could have happened... did.