What is a safe way to remove Graffiti without damaging the undercoat?

When one of our fellow citizens runs around at night and decides to paint all over your business, home, commercial building, parking ramp, retaining wall etc etc it causes you a headache.  Their is a new product that we used recently that can remove the graffiti coating and leave the under coat safe from marring, scraping or the  cumbersome task of having to fully paint everything to match.
There are 2 types of products available (both are lemon based out of Australia).  One is for graffiti done on softer surfaces like a previously painted wall and one is for graffiti done on hard surfaces like block, retaining wall, ferrous steel.
On this job a large building in St. Paul was "tagged" and the property manager called us.  We were able to fully remove the graffiti without damaging the pre-finished aluminum siding.  There was no marring and no scraping.  Also, we were not required to prime and paint the surface (which could have voided any manufacturer warranty)
For safe, effective graffiti removal call Complete Custom Painting
651-336-0561 cellular phone
www.completecustompaint.com

  AFTER GRAFFITI
 AFTER CLEANING
  Product hoisted up 30 feet with rope.

  Cleaning in Process.

PRODUCT APPLICATION