In these tiny amounts you can add all kinds of liquids to fuel or engine oil without too much harm over the short term.
A fact that many companies take advantage of, selling fuel and oil additives made from cheap mineral oils and solvents.
I don't believe the oil and fuel producers are selling a product that needs improving. It doesn't seem like it, but there is competition as in any industry.
Some people pour acetone/2cycle oil/xylene/etc. mixtures into their gas tank and swear it gives them better milage.
I prefer filtered air and clean fuel down my intake and nothing else. Can't go wrong there.
Besides: If you got a PCV hooked to your manifold - you get plenty of lube to your top.
Just don't pull the head to scrape off the crusty deposits...Yikes!
