Usually, far too much lube gets used on folder joints. It stains and drools and collects dirt and lint.
Same thing with the actions and hinges in shotguns. Use very, very little.
In some gun stores, you can buy a little squeeze bottle of very thin oil called a "Gun Oiler."
The smallest little convenient droplets at your command.
I've got one. Was in a Beretta field cleaning kit. More than a lifetime supply.
There are hypodermic syringe needles made with square blunt tips.
I have a few for reloading ink cartridges in some drawing pens.
They would make good tips on any kit oilers.
A bit off topic, but I always store my shotguns muzzle down, so that any excess oil doesn't seep into, and weaken, the wooden stock.
If I do oil a folding knife, which I don't find necessary on Swiss Army knives, I apply a tiny drop using the point of a pin. A little goes a long way.