Subscribe | UPI Odd Newsletter Subscribe SAN FRANCISCO, Feb. 17 (UPI) -- Cleaning up an annual Valentine's Day pillow fight cost the city of San Francisco about $5,000, officials said. The eighth annual "Great San Francisco Pillow Fight" started at 6 p.m. Thursday and ended with the Justin Herman Plaza being covered in feathers, synthetic pillow stuffing and other debris, Bay City News reported. Hundreds of people participated in the event. Advertisement At about 10 p.m. Thursday, a cleaning crew moved into the plaza to sweep up feathers and used steamer machines -- a job that cost the city between $4,000 and $5,000, Department of Public Works spokeswoman Rachel Gordon estimated. "It's messy but becoming a regular San Francisco Valentine's Day experience," Gordon said. The cleanup process has become easier over the years as the department becomes more experienced in clearing out the feathers, Gordon said. Read More Feathers fly during Int'l Pillow Fight Day Florida joins in pillow fight Pillow fight breaks out in San Jose