put a few drops of oil (used chain lube) inside the outer housing
Mmmmnnn you shouldn't really need to do this. If your cables are sticky, replace them. Good quality modern cables have low-friction liners so they don't need any lubrication - adding oil just drags grit and grime up into them so they wear out even faster.
A two-pack of Shimano 105 brake cable with inner/outer/nipple/cap is what, twelve quid? Not much point in being a cheapskate about it!
Mmmmnnn you shouldn't really need to do this. If your cables are sticky, replace them. Good quality modern cables have low-friction liners so they don't need any lubrication - adding oil just drags grit and grime up into them so they wear out even faster.
A two-pack of Shimano 105 brake cable with inner/outer/nipple/cap is what, twelve quid? Not much point in being a cheapskate about it!