One of the most famous graffiti artists to have been involved in legal disputes over copyright is Banksy. The British artist, who maintains his anonymity, has had to navigate the tricky balance between asserting his rights over his works while avoiding potential legal consequences for creating them. Banksy's works are often created on buildings without the owner's permission, which technically makes them acts of vandalism under UK law. However, to the best of my knowledge, Banksy has not been held financially liable for the cost of removing or painting over his works.
The issue of an artist being held liable for cleanup costs in a copyright dispute has not been definitively addressed by the courts, at least not in any high-profile cases that I'm aware of. This is likely because most graffiti artists, like Banksy, maintain their anonymity precisely to avoid such consequences.
As for the question of revenue from the infringing use of the art being used to cover cleanup costs, this would likely depend on the specific circumstances of the case and the discretion of the court. In general, copyright law would entitle the artist to any profits derived from the unauthorized use of their work. However, a court might potentially offset these profits against any damage caused by the creation of the work, such as cleanup costs.