If you're talking about the BM mini-rukus (or ANY folder, for that matter).....
What I do with my folders (I don;t have a Rukus) depends on what I got it "dirty" with. If its got blood or similar gunk on it, I clean it with Simple Green and a toothbrush (this combo works great on teeth too!). If it's got tape residue or other sticky stuff, I'll start with WD40 and the toothbrush followed by the Simple Green method (this combo is only recommended for teeth if you've been eating tape or Elmer's white glue).
After the "dirt" is cleaned off, or if it's already clean and I just want it "edible" clean, I wash with HOT water and dish soap, followed by rinsing with HOT water (note I said HOT water, not hot water). Try not to get water in the pivot area, but a little always seeps in. Dry quickly and, while the knife is till HOT (note: not hot, but HOT), blow out with compressed air and oil "lightly" with 3 in 1 or a machine oil or any fancy miltek-1 or other high-end lubricants.
S30V is a high-carbon, high-vanadium "stainless", but it can rust....though it won;t if you take care of it