HOW DO I BRING 190 PROOF ALCOHOL DOWN TO 80%?

We would suggest diluting the 190 proof alcohol with distilled water or any highly filtered water to remove any particulates or contaminants. Measuring a 50/50 ratio distilled water to distilled 190 proof will give you 95 proof which is roughly 47.5%. There are measuring devices you can purchase at testing supply stores that will test percentage for more accurate applications.