What Is the Best Lubricant for Door Locks? Emerald Doors OLUBE PARKER O RING SEAL LUBRICANT National Fire Supply if you need to lubricate locks id recommend 3 in 1 oil. way better than wd40 been using this for years with no issue GRAPHITE LUBRICATION , The benefit of using a graphite lubricant (rather than oil) is that the graphite leaves no sticky residue that may later attract dust., This is why its often best to use a Lubricant Care Spray for Cyclinders ABUS Kasp Graphite Powder: Stop Locks From Freezing!