Earlier quoted context omitted.
This makes me wonder if it would have been possible to, instead of using something that causes significant harms to health, instead something which just causes a rather unpleasant experience. But, I guess one important thing is whether such an additive is compatible with the altered substance still being usable for the purpose for which it is being made available. Now, presumably something as simple as “dissolve larg…
I think that's what they ended up doing, post-Prohibition. A bottle of rubbing alcohol from the drugstore is either isopropyl alcohol, which is toxic by itself but not intentionally so, or ethanol mixed with a denaturing agent that's more benign than methanol or whatever they were using back in the day.
Choose your poison:
27 CFR § 21.151 - List of denaturants authorized for denatured spirits. https://www.law.cornell.edu/cfr/text/27/21.151