Which alcohol should I use?

[SMOKINV6]

I can get 70% isoprpyl (sp)? from the hospital my wife works at pretty cheap of I can get some from my work that just says 67-63-0 when it says contents and flash point of 141 on the container but no %. it is isopropyl thou. I want the proven safest stuff for my engine so any recomendations are welcome Thanks.