Touch up removal using Acetone confirmed.
So I tried to touch up on the scratch and stone chip using the OEM touch up paint. First time using that, so I did NOT shake it well and ended up with uneven color and big blobs.
Edit: I used the official abrasive, tip, brush, clear coat 4in one pen. Seems like an OEM Dupli-color product for Subaru. I have the dark metallic gray, so the metal color condensed together and looked ultra bright bird poo......
Tips on Touch up:Shake it really really well, I prefer the brush as the color and texture is more even. Metal powder also seems stuck in the mechanism of the tip so .....
Result on removal: This result is only focused on the OEM touch up on 14"-18" Subaru (does not mean same result on others)!! Acetone is the key substance in nail polish and a lot of the paint thinners. So instead search car paint thinner desperately, all local hardware store should have acetone. Be sure to use it in well ventilated area as it is poisonous, flammable and fume is bad.
So I used cotton swab, dabbed in Acetone then wipe the touch up and touch up clear coat. The fully cured touch up paint and clear coat were wiped off effortlessly. Some other auto forums had claims that acetone hurt the factory paint/clear coat. I did not find problem present. I did have other clear coat scratch so I tried it on. The factory clear coat was not affected based on eye inspection.
That is my experience and tips with touch up.