Why not sandblast the walls of the Barrack Entrance?

Not started
The walls of the Barrack entrance have become weathered and green. The entrance that was built in 1901 dedicated to the 2nd volunteer Batallion - the Cheshire Regiment is in need of restoration. Imagine if it were sandblasted back to its former glory?

Why not sandblast the walls of the Barrack Entrance?
Model
NIKON D3400
Aperture
f/13.0
Focal Length
18
Exposure
1/30
Iso
360