I must have watched 10+ Demonstrations at the ISSA in Amsterdam on Graffiti removal. Every one I saw destroyed or damaged at least part of the surface they were trying to remove the Graffiti from. I still insist to remove you need to pre wet the wall or substrate paint on Aqua Mix Sealing & Coating Remover and allow it to dwell for 20 minutes then agitate and pressure washer it off gently with heat if possible. All this attacking it with super high pressure and heat always seems to do damage as far as I am concerned.
Kev Martin
Marble Life Ltd