If it were my building I’d paint over the graffiti with brown paint and call it art.
You just need to make a big freaking deal out of it that you are using NON_AEROSOL PAINT AS TO NOT DAMAGE THE OZONE LAYER AND PROMOTE GLOBULL CATASTROPHIC WARMING/COOLING.
The “artist” can buy carbon credits with his 5Mil then spend the rest of his life in jail for being an idiot and spreading it around until we all were involved in this thing against our wills................!!!