What's the best oil for a pocket knife?

put only edible oil on it! a knife is used to cut food, it's useless if you sprayed toxic products on the blade.

I'm sure this has been pointed out here before, but I'll say it again: WD-40 is a solvent, not a lubricant. Use it to loosen a rusty bolt. If you want to lubricate and/or protect something, use oil. Mineral oil works quite well for blades.

A single drop of 3-in-1 oil works wonders. Half a drop if you can manage it. I have also used sewing machine oil and hair clipper oil with great success. One drop should last 6 months. Any lighter oil will just evaporate.

+1: Food grade mineral oil so I can use it to cut food. It never sits long anyway.

Sentry Solutions makes a lube that drys completely and works great.

I've been using Victorinox Multi Tool Oil for quite some time on all of my folding knives/tools. http://bit.ly/Ana0JT Comes in a small handy container. Lasts for months. One drop on every hinge is all you need.

I primarily use stainless steel pocket knives as my every day carry knife. As such, I don't need to worry about oiling the blade. I still do sometimes (out of habit), but I don't need to. The knives I get tend to have good bearings/swivels as well and don't need much maintenance. On my carbon steel blades I use a variety of oils. For display/heirloom/investment knives I use break-free clp. I've never found a better way to keep guns or knives from corroding. For other knives, that I might end up eating with or using, I use mineral oil or 3-in-1. It's a rarity when I use one of them for food, so I'm not worried about a little 3-in-1. It builds character.

Silicone lubricants would probably work well and they won't likely cause an oily spot on your clothes.

White Lightning is a liquid lubricating wax I've used before. It's great, dries and stays, won't leak off into the material of your clothes and lubes nicely. I've been working on the same bottle for about 8 years!

CLP as mentioned above is great for all around use but not food grade (as also hinted at above). People love to crap on WD40 but it's a great water excluder so if you plan to lube frequently and it's what you already have it's fine and you'll have zero problems. Large amounts of anything liquid will only attract crud to your pivot, so using a q-tip saturated in your oil of choice is a nice way to control application.