Family member bought used BMW Z4. I hope to be involved with cleaning it up soon, but I need some advice on the windshield etching. I have searched and read about several products and procedures, but I would like to know if anyone has had any success using regular car paint compounds by hand or machine. I have a rotary, PC-DA, and can work by hand also. I have M105, UC, ScratchX, and several other polishes and cleaners. Basically, what I would like to know is, can I make any progress without buying a dedicated windshield kit?Feed back please