The wall is plastered with wads of gum in a kaleidoscope of colors, some stretched and pinched into messages, hearts and other designs. People also have used the gooey gobs to paste up pictures, business cards and other mementos.
Emily Crawford, a Pike Place Market spokeswoman, said that following a busy summer season, market leaders decided now was as good a time as any to wipe the wall clean. But they expect people will start leaving gum on the space again soon.
"It's an icon. It's history," said onlooker Zoe Freeman, who works near Pike Place. "The market is famous for the gum wall. But it also draws rats."
Pike Place Market hired a contractor, Cascadian Building Maintenance, to take on the cleaning. They chose steam over pressure-washing to conserve the historic market's brick walls.
On Tuesday, a fruity, sweet smell wafted through the alley as workers in protective suits blasted the dried gum with moist air.
"I just hope that the citizens of Seattle don't hate me for removing the gum wall," said Kelly Foster, the contractor's general manager.
People first began smooshing their gum to the wall while waiting for shows at the nearby Market Theater. Since then, the "gum wall" has expanded beyond one wall and onto other walls of an alley, pipes and even the theater's box office window.
Crawford said the cleaning crew will collect and weigh the gum each day it is removed. The cleaning is expected to take three days.
By Crawford's rough calculation, there are about 2,200 pounds of gum on the walls.
"We'll find out at the end of the week how right my guesstimate really is," she said.
Market officials hope to contain where people put their gum in the future but say they aren't holding their breath.