Yes, it's the additive that I think causes the problem (streaking). Otherwise it's just pure alcohol as you say but I find it being watered down these days. The Metho on my shelf (next to the 100% Isopropanol) is labelled as 95% Ethanol so presumably the rest is distilled water because it's cheaper. It's great for cleaning all kinds of stuff but I don't clean lenses with it.
Originally Posted by Tom1956