Holy shit, Lifehackable posted something useful.
Except Rohypnol isn’t salty - GHB and other date rape drugs are kinda salty, but Rohypnol isn’t
Rohypnol is BITTER. If your drink is saltier, it’s GHB, if it’s bitter it’s Rohypnol.
Either way, keep safe, friends.
Source: http://lifehackable.tumblr.com