For the abused, abandoned knives I pick up, that are just really gritty, and stubborn to get open, I find that a bit of Kano Kroil, will help get the blade open. For general lubrication though, I use whatever's handy like CLP Breakfree, or Lucas's gun oil, that I grow more fond of all of the time. For the blades I feel like Ballistol is as good as anything for corrosion resistance.