Laser erasers? Example, one used on some monuments in Florence: https://www.lasersystemseurope.com/news/infrared-laser-used-remove-graffiti https://www.lasers

Laser erasers? Example, one used on some monuments in Florence: https://www.lasersystemseurope.com/news/infrared-laser-used-remove-graffiti https://www.lasersystemseurope.com/news/infrared-laser-used-...