I quit the auto paint industry because a friend of mine had his sinus removed due to cancer. He was a painter, I was a manu paint rep for 10 years. My best friend at the paint company Sikkens has had 2 brain surgeries since and now is a 52 year old one eyed, no drivers license, walks with a walker, and wears glasses to prevent seeing double vision. All the cans I sold had a skull and crossbones on it because it is poison. I would show that to all my customers and tell them to wear gloves and respirators when cleaning spray guns and mixing paint at the bench and while spraying primer and while dry sanding...chromate has been removed from primer for about 10 years now. Bondo is made of styrene (bad). etching primers use phosphoric acid. ALL hardeners contain cyanide...that is what makes the molecular linking occur and what makes 2 part acrylic urethane topcoats dry so hard...oh ya, a typical spot repair paint job (2-3 panel repair) sends fluorocarbons to bust our ozone layer - about as much as 2 cases of aerosol cans of hairspray...you don't want to know what kind of emissions they shove out the stack at the auto factory - and the air quality rules in europe are much less than here. One more thing - a respirator does not STOP the bad stuff, it only filters out most of it, actually does not catch isocyanates. A fresh air device is the only way to eliminate exposure.
Use Naptha, use gloves, use a respirator, and a big exhaust fan!