In the evening on Sept. 20, Shaun Deaton, 44 dumped red paint on one side of the monument and wrote an obscene message.
Deaton's message at the base of the monument read, "Have you been f----- by this ... Gov says tough s---.", according to NBC News.
U.S. Park Police charged Deaton with trespassing, tampering and vandalism.
The monument was temporarily closed, as preservation crew members began the clean-up process.
"The top layer of paint is coming off and the pigment that seeped into the stone will be treated with many rounds of cleaning product application."
The National Mall's preservation officials were optimistic that their cleaning, along with ample sunlight, will restore the monument.
The site was reopened on the morning of Sept. 21, though authorities did not say how long the restoration process will take.
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