Removing Paint

[Gunnut]

I bought my 94 LS400 about 2 months ago. I am just now getting around to working on the exterior finish. It is good shape but needs a good claying and polishing.

One area I need help on is on the passenger side down low. Apparently the prevous owner picked up some road paint from lane striping. I have no idea how long it has been there.

What should I use? Denatured alcohol? Mineral spirits. I don't want to remove the good paint, just the bad paint.