Just one additional thought to add to the others here. If a razor isn't completely dry, oil can trap moisture against the blade, so unless I'm not going to use the razor for a week, I don't oil them at all and I never oil them within 24 hours after use. May not be necessary, but it has worked for me, and I live a a beach town with .5 miles of the Atlantic, so it's fairly humid, always, as I imagine Shanghai is.