Carmen Lucette Tisch allegedly leaned against the painting, punched it, slid down it and urinated on herself at the Clyfford Still Museum on Dec. 29, The Denver Post reported.
"It doesn't appear she urinated on the painting or that the urine damaged it, so she's not being charged with that," Lynn Kimbrough, a spokeswoman for the Denver district attorney's office, said Wednesday. "You have to wonder where her friends were."
Tisch has been charged with criminal mischief for the incident that caused about $10,000 damage to the painting, Still's "1957-J-No. 2." The woman allegedly committed the offense with her pants down, the police report said, and hit the painting repeatedly with her fist.
Ivar Zeile, owner of Plus Gallery in Denver, said that, if the canvas wasn't pierced, the painting can likely be restored.
"It does damage the piece, though, even people just knowing that happened," he said.
The painting was valued by the museum as being worth between $30 million and $40 million.
Still, a North Dakota-born artist, is celebrated as one of the most influential abstract expressionists of the 20th century. The museum opened Nov. 18 to showcase his 60-year body of work.