Ballistol is biodegradable, non-carcinogenic and good for wood/metal/leather/plastic/rubber. It cleans and lubes. I can think of no other store bought product which fulfills all of these criteria; hence, I use and love it.
All it is is mineral oil, vegetable oil and some acetate and alcohol. Plain and simple, great stuff. All the other solvents/lubes/"water displacers" pale in comparison.
If society ever collapses and I am no longer able to find Ballistol though, I'll just go back to hot water and random grease.