Pictures, business cards and other mementos were also attached to an estimated 1 million pieces of chewed gum stuck to the wall. But now authorities have used industrial steam cleaners to clean the wall in the Pike Place Market.
A spokeswoman for the market, Emily Crawford, said despite the wall's popularity, it was in urgent need of a clean. Zoe Freeman, who works near Pike Place, said: "The market is famous for the gum wall. But it also draws rats." She added: "It's an icon. It's history."
The gum will be weighed by the Pike Place Market Preservation & Development Authority before it's thrown out.
People began putting their used gum on the wall while waiting for shows at the nearby Market Theater two decades ago. It later spread beyond the wall and onto nearby pipes, and even the theatre's box office window.