The Laundry Receipt is a receipt for the Laundry in Chinatown, San Francisco.
A Dragon was customer of the Laundry and held a receipt when he was killed by Mic Stone and another mutant outside the Canton Bank. The Receipt was found on his body and taken by the Manhunter.
However there was no address on it, and the Laundry was closed.
On Day 3 The Manhunter entered the Laundry, and showed the Receipt to the girl working there. She mentioned it to another man (perhaps also a Dragon) and prompted him inside. He was hit by the other man.