Wow, 80 grit! That's very coarse. I start with 400, or 240 if the pitting looks bad, and if that isn't removing the pitting quickly enough, I will try 120, but it then takes forever going back up the grades. I've pretty much given up on blades with pitting bad enough to need 120 grit.

I've always used the paper dry, I hadn't thought of using wd40.