I don't think 99% is better for soap than 91%. The amount of water in 99% is so low that it evaporates very quickly. The 70% evaporates more slowly and is considered better for disinfecting surfaces for that reason. The 91% is somewhere in between. But according to sources that make it, the 91% will remain 91% even as it evaporates, whereas while the 70% evaporates, (in the bottle for example) the concentration of alcohol in solution does change. And it is true, it can be hard to find. I think you'd have better luck trying to find it at a store than caters to folks who do their own electronics repairs. One of our members mentioned one day that she had to take soap away from her dad because it looked like food and he was eating it. Our sense of taste diminishes as we age, and it's really an issue when your sense of taste can't tell your brain that this is bad for you. And then there is the whole pica eating disorder - eating non-foods; lot's of people have pica disorders, and eating soap is one example.