What other ingredient? When asking questions you should include more information, otherwise how can we know if you should use it or not? Maybe the other ingredient is just another name for acetone, maybe its water, maybe its something toxic, maybe its some other volatile non-toxic component which wouldnt be bad ... ? We can only know if you are specific about it. Also as suggested in the FAQ, whenever using a new solvent, check for the MSDS of the product online to see if it has an accurate list of the ingredients. Though doing an evap test is not fool-proof, it is for sure recommended, as said above.
With IPA its more or less the same thing, it depends, is it pure? For making changa, it doesnt matter the strenght of the IPA, as long as the other ingredient is water and nothing else. The more water, the longer it will take to evap/dry, but it will work perfectly.
As poster above said, ethyl alcohol (ethanol, grain alcohol) can work too, if you can find that, keeping it foodsafe.. Even vodka would work, though im not sure if it would leave a little bit of taste, I would guess not much though