You can’t blame people who are afraid of germs for hating public transport. It’s well-known that, during the winter months, the subway is a veritable petri dish of bugs that can lead to colds and flu. But how do you convince people to keep their hands germ-free in the summertime? That was the challenge facing Ogilvy and Geometry in Australia. So they coated handrails, turnstiles, elevator buttons and other sensitive points on the metro with an invisible powder. When combined with an ultra-violet camera, this showed commuters exactly how many germs they were picking up thanks to the sticky humidity. To compensate, they were offered a squirt of Aquim hand sanitizer.