I have an attachment for my pressure washer . But for normally I use an in expensive device called the underwasher that connects to your standard hose . check it out on theunderwasher.com. https://youtu.be/Vyfh8YFGTG0
As stated with proper wash techniques you will be able to keep the damage to a minimum. As I am a fellow Black car owner . I learned long ago that if I'm not washing it then don't touch it . LOL.