My pick-up truck and house were covered with spray painted graffiti. I obtained a quart of Smooth Max®. When I got home, my son and I sprayed the graffiti on my pick-up - just like spraying window cleaner - and it came right off. I couldn't believe it - it was amazing. It took just a few minutes, and all the graffiti was gone and my truck was not harmed in any way. Then I used up the rest of the container on the wood siding of my house.
Note: Dawayne had before and after pictures available, but due to the obscene nature of the graffiti, we have chosen not to put them on our site.