Fuel Additives

I have been reading around and found that some people put acetone in their fuel tanks to gain some power and clean out their system. I have also heard that Isopropyl (a key chemical in acetone/alcohol) is also a major additive in 91 octane fuel. Is this true? What other additives does 91 octane contain? I have also seen a few additives to raise the octane to 100. What chemicals are in that? Is it possible to make my own fuel additives to raise the octane level to 100 for less the a couple dollars a fill? It's an interesting topic . Thanks.