Diesel, kerosene, any oil goes on the stone for me to float the grind away. Spit works, but I hate to waste my precious bodily fluids.
I do try and oil my knives that see outdoor use.
For sharpening, I use the cheap, WM Tech 2000 "Spray Lube," which for all I can tell is 1K in a spray can, maybe some mineral spirits? I don't use it or trust it as a lube or rust preventive. Inexpensive, floats the particles well, handy, drips off the stones and does not get sticky over time.
On diamond plates - water, or dry and then cleaned up with water, Dawn and a stiff nylon brush.
For me, "sharpening" runs the gamut from a 1" x 30" HF belt grinder to wet/dry abrasive paper, some actual stones and diamond plates, with strops to polish off the edge.
Oh, it does do well in bores too. I smell a sharpening thread coming... Maybe should have saved this.
Back to "knife lube" - the main reason for the Bore Butter is to protect the fine edge and polished bevels from oxidation. Maybe a bit anal, but my woodworking habits are hard to ignore when I work on a knife's edge.