Can I use cutting compound to remove graffiti sprayed on my car?
I've used T-Cut in the past (albeit on a test car panel), and it worked great. Apply it onto the whole body panel (although, if you're going to do this, I'd personally commit to the whole car) and focus particularly where the paint is. However, make sure that you don't keep rubbing too much and too hard, otherwise you're literally going to burn through the clear coat and straight into your base coat.
The idea of T-Cut is to strip a small layer of the clear coat, making the rough layer refreshed to a deeper, smoother layer. If you go too far with the clear coat, you're into the base coat which is the paint layer of colour.