I've never seen "rubbing alcohol" that had crap in it, it always evaporated clean for me. At least in the states, rubbing alcohol is 70% or 91% (the stood you want) isopropyl alcohol. It does not contain a denaturant, as isopropyl alcohol is not drinkable (it's only mildly toxic though).
That's what I use for cleaning off flux, as well as many other cleaning operations