Depends.
The hard part isn't matching the scratch, it's the surrounding area and whatever surface coating is on the aluminium. Many times it's anodized, to harden the aluminium and offer some protection from scratches etc but that's a coating that's almost impossible to replace without special tools and equipment. So if the surface is anodized, you are out of luck.
Sometimes it's just a clearcoat paint, really thin but protects the aluminium from oxidizing. If that's the coating, you could buff out the scratch and give it a quick shot of clear then use a clay bar to remove the overspray and blend it back in.
If it's pure aluminium, no coating, that can be the hardest to repair because there's no coating to hide imperfections. Most use everything from steel wool to a scotch pad to a wire brush, even using a wire wheel on a dremel. But replacing the 'brushed' look and getting the refraction angles right is a nightmare. Get it wrong and from one angle the repair is invisible and 'gone' yet from another angle shows up like a full moon in a star less sky.
At a minimum, I'd say a lot of time and patience with a X-acto knife might be the best bet. Use a magnifying glass and ruler and recreate the vertical 'brush' lines. The scratch is visible because of the change in the 'peaks' of the brush, if you re-do the brush, the scratch loses its affect, pushing the 'peaks' back straight.