Oil is oil. Gun oils just have different additives.
Oil it with "Crosman Pellgun oil", "RWS OIL" or "Gamo Pellet gun oil" Wipe it down. DO NOT USE Household oil or 3-N-1 oil. They will damage the gun. Put a drop in the barrel and run a swab through the barrel. If it's a C02 gun then put a drop of oil where the C02 bottle fits into the gun and charge the gun. If it's a springer type of rifle, put a drop of oil in the oil hole in top of the rifle barrel or in the loading chamber. DON'T over oil the gun.
I suggest Crosman Pellgun oil or RWS pellet gun oil.
The main purpose of gun oil is to lubricate the moving parts of the gun in order to reduce heat buildup. Gun oil is used to prevent cracking of the metal as well a wear and tear upon firing a rifle.
Never use Motor oil on a BB gun. It will eventually ruin the seals and O-Rings.
You rub oil into it.
Yes, usually contact oil (Pellgun oil).
sure, will work well
This BB gun was made by WHO?
Any light machine oil, including motor oil in a pinch.
There is no such thing as an oil free pneumatic nail gun. Every nail gun requires oil every day you use it. In answer to your question, yes, you can use any nail gun with an oil lubricated compressor. The way the compressor gets it lubrication has nothing whatsoever to do with the tool you are using. The compressor is just supplying air to the tool.
You are better off using gun oil, or at least a machine oil like sewing machine oil. Vegetable oil kind of smells, olive oil works better, but these organic oils are not as desirable as gun oil. You can use baby oil in a pinch, for a few months at a time. It is better than nothing, but you should wipe it down and replace it with a decent gun oil when you have a chance.