Don't lube it. Hear me out on this one. When I first started carrying Emerson knives, I got the gunk out and used some oil. The oil would leak onto the lock face and cause the lock to slip. So I decided to switch to grease and use just the TINIEST bit possible. Worked like a charm at first. Then I started to notice that pressing my thumb on the blade caused a tiny bit of vertical play. I didn't think too much of it, so I dealt with it. Then one day I waved the knife and the lock slipped again just like when it had too much oil on it. I thought "what the heck?" and tried waving it again. The lock slipped during waving again. Took the knife apart to find that the TINY amount of grease I used had slowly worked it's way onto the lock face over time, hence causing the same issue as before. Then I said to heck with it - Emerson calls their washers "self lubricating" so I'll run it dry and see what happens. I got all the gunk out and put it back together and right away I noticed that all lock rock was gone and the lock didn't slip. I also noticed that I felt NO difference in smoothness from when it had grease in it. I get the idea that Emerson knives like to run dry at this point. I've been carrying mine with no lube at all for almost a year now and it remains as smooth in action as the day that I cleaned the lube out, which is to say super smooth (smoothest I own).
Just clean it out and run it dry and keep on breaking it in. I also recommend lightly sanding down the pocket clip side. This helped make waving work better for me by causing less friction on the pocket plus I don't tear up my pants as much.