Next the children head to the sinks for the ultimate test. They understand better when I tell them to count slowly to 20 or 30 while washing their hands or to say their ABCs or sing Happy Birthday before they turn off the faucet. Back in the classroom, Partridge prepares the children for their results. I can always pick out the children who bite their nails, because the GlitterBug potion will still be in the creased around their fingernails. It also sticks to the natural creases of all the children's hands.
Partridge remembers one particular classroom in which the black light proved very effective.
When I turned on the black light, all those stamps glowed and you could tell which children hadn't washed their hands since they left the fair the night before. The program also reaches the parents as the children rush home to tell about their day. Partridge has found the program can also be used effectively with adults. When the person touches the handout and then scratches their face, the powder will show up under the black light. She says adult groups are very surprised and sometimes embarrassed when the black light is turned on.