Malalim na ba to the feel yung scratch? Run your fingers across the scratch if you can feel the depth of it. Kung malalim na sya to the point na lumabas na yung white base colour then you have no option but to have it fixed at any detailing/painting shop or sa casa. Kung hindi pa naman as you said "light scratch", then it can easily be fixed by performing the following in order: (This is what I do with my mystic blue monty)
1) Wipe the affected area with a damp microfiber cloth. Wait until it dries. This process is just to remove any unwanted dirt, dust, sand, or similar which would eliminate any further scratch generation while doing below process.
2) Apply
3M scratch remover and gently rub the affected area with a microfiber cloth over and over. Repeat this process until the scratch is no longer visible. Polish/wipe any residue with a clean microfiber cloth. You're not done yet...
3) Apply a small amount of
3M Hand glaze to restore that deep mystic blue colur. Polish/wipe any residue with a clean microfiber cloth.
4) Apply a synthetic wax. The one I use is either the
3M Performance Wax or
Microtex Nano Gloss. Polish/wipe any residue with a clean microfiber cloth.
5) For best results, I top it up with either
3M Quick wax or
Microtex NanoSliq.
Hope this helps. Good luck.