Although you’ve said it’s a surface scratch, how deep is it? If it fails the finger nail test (i.e. it‘s deep enough to ‘catch’ when you run a fingernail over it) it’s probably too deep to polish out completely, although you may be able to improve it with polishing.
If it’s not too deep and if you know someone with a DA polishing machine, they can probably remove it quickly and easily with the right combination of pad and polish and is likely to give the better results than hand polishing. However, if you’ll be attempting to remove it by hand polishing, then you could try a product such as Farecla G3 Scratch Remover or Meguiars Scratch-X on a sponge applicator, once you‘ve washed and dried the car. I’ve not used either of these or any alternative manually applied scratch removal products so can’t vouch for how effective they are, but there may be forum members who have used them and can provide feedback on their experiences.
Be sure to follow the instructions and don’t apply too much pressure when using these abrasive scratch removal products, as over-enthusiastic use could increase the risk of damaging the clear coat.
Scratch-x is great stuff. I’ve had some nasty clear coat scratches, which have come up great after using the compound (I used a D.A. Polisher, by hand is a lot of effort). You may need to wet sand first if it’s deep, try super fine grit 1500-2000 and a sanding block (go easy though, don’t cut through the clearcoat). If the scratch has gone through the clearcoat and in to the colour paint then would probably be worth checking out professional SMART repair. It can be a massive pain matching paint repair to the original paint, it can stand out more than before the repair. Or get a decent body shop to do the whole panel.