What are bad alcohols I should look out for?
SD alcohol aka denatured alcohol, propellant, Isopropyl alcohol (like Americka said).
Fun fact I learned in college Chemistry: denatured alcohol is actually regular drinking alcohol (beer/ liquor), but they are required by law to denature the alcohol and add poison to it to make it non-consumable or else they will be charged liquor tax which is higher.
Generally, the product you'll want to watch out for bad alcohols in will be a styling product like wrapping lotions, serums, and yes, a few leave-in's. They add the alcohol coz it dries faster and provides hold.