"A tiny drop of household oil (or vegetable oil) can help too"
What are they saying? Are they quite mad? You should NEVER use edible oils to lubricate machinery of any kind (nor should you use mineral oil to dress a salad)! The only thing edible and mineral oils have in common is that they are insoluble in water. Edible oils are, chemically, triglycerides, which are big E-shaped molecules. Mineral oils are hydrocarbons, ie, chains of carbon atoms with hydrogen atoms attached, the smallest of which is the gas you cook with. By the time you get to eight carbon atoms you're in petrol territory and they get more viscous and 'oily' the more carbon atoms there are.
The upshot of this is that edible oils, being edible, will be digested by any passing bacterium and will go rancid, sticky and disgusting. Mineral oil will evaporate slowly and, if it's the correct type for the machine in question, shouldn't leave a chemical residue although bits of worn-off bearings, fabric fibres, etc, might cause a bit of a mess if the machine isn't maintained.