WD-40 sucks. Period. Gave my last can to my ex-wife.
The problem is that it is basically mineral oil with surfactants and a carrier. The mineral oil tends to gum up (incidentally, there was an article about the WD-40 company in the WSJ 6 or 7 years ago; they mistakenly said it was made of surfactants and mineral WATER, obviously a typo, but you still see people who should know better quoting that article).
The advantage of Sentry (Tuf-Cloth, -Glide, etc.) and Corrosion X products is that they have an extremely low surface tension, and will penetrate everywhere, while bonding to the metal; the thin film technology will even penetrate UNDER corrosion, and bond with the undamaged metal underneath.
Oil will simply coat the metal, including rust and corrosion, and not stop the rusting or corroding.
Try these new products out; you will be impressed. They are widely used in the knife industry. Walt