Any tips? Trying to think of a way to do it withough scarring the rocks all up, and without using HAZMAT chems. Saw a bunch on the Santa Rosa Truck Trail the other day. :mad3::mad3::mad3:

sand blast I would think

If you could

ZEP Makes a product.....
Zep Erase® - Chlorinated Solvent Graffiti Remover. Highly Concentrated Aerosol to Remove Graffiti on all surfaces. 24oz. 12/case
ZEP product # 031101

Available from: http://www.supplyhero.com/Tool/Zep/Index.htm

Their product # DYM 07820

Hope this helps. There are several other products that are available maybe from a janitorial supply place.

Dennis