Mark, I know you referred to the markings as grease, and these do exist. The ones in grease marker that I have found have generally been on top of the black paint. Any attempt to raise these usually obliterates them. The paint markings under the the black paint are pretty resilient. I recently got to the paint marking on my coupe by stripping. I tried several less intrusive methods with little success. I then used Jasco brand stripper. I left it on until it just began to wrinkle the black paint (less than 5 minutes). I then used a plastic scraper and it revealed all the markings without damaging or destroying any of them. I'll be posting a "details" log for the car soon. I have several more photos to shoot of the little details and original markings I've found throughout the car. The log will include a shot of the markings on the radiator support.