I used a paint pen on my old 325i (before the insurance adjuster took a look at it after the accident). After the paint dried, I gave the area's I touched up a coat of 3M wax. It did blend the new paint pen touchups a little bit with the surrounding areas.
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1994 530i 5 speed - RIP due to a dipshit that can't do overshoulder checks and ran over the front end with his Jeep!

1989 325i - RIP due to a knucklehead that rammed the car in the butt doing 50 km/hr while I was stopped at a intersection!!