Everclear works best, and a big bottle of that goes a very long way for cleaning parts. Works great, leaves no residue. Not toxic unless you really drink more than a few swigs.
Incorrect. "Rubbing Alcohol" is isopropyl, water, and generally some kind of oil.What he describes is called denatured alcohol in the USA. Ethanol with methanol and often a few other solvents. Works great as a degreaser, but attacks some plastics..
I generally use 99% isopropyl for cleaning electronics, but also use denatured alcohol for some tasks.
Not for a 91% solution. The vapor and liquid have the same composition. That's why it's impossible to obtain a higher concentration via simple distillation. I think that also means it is slightly more volatile than pure isopropanol. The 91% stuff should actually evaporate as fast or a little faster.But maybe the higher concentration makes it a better solvent.