Armaglaze, an anti-graffiti coating

See "Graffiti artists' spray erased by Armaglaze"

From the article:

Armaglaze, a paint-like coating that comes in clear and tinted versions, was designed specifically to combat graffiti and save wear and tear on building exteriors. Soda and sand blasting can leave a marked surface, Lee said. So can other chemicals used to clean the spray paint tags.

Lee's product isn't the only one on the market. There are other similar products and what he calls "sacrificial coating" that creates a removable barrier between a building's surface and graffiti. With Armaglaze, you can use an array of cleaners to take the paint off, but leave the coating intact. The coating lasts three to four times longer than traditional paints, an added bonus. Lee's product is available in both a solvent base and a water base...