Fertilize your lawn and change your engine oil, then w/o washing your hands, open your vehicle door handle, drive through a military gate and chances are strong you will pop for “HME” residue. Unless the vehicle HAS explosives, its likely a false positive positive.....
TSA pulled my bags out for additional inspection once because I pulled them across my father-in-law’s lawn right after he had fertilized it and the sensor tagged them for the presence of explosives.
Had that happen once. Helped a friend, who is a pharma rep, pack samples of heart medicine.
I wash my hands.
I was thinking about a hat or shoes worn at a shooting range...that might test positive at TSA inspection too?