Determine the size of the project and the depth of the scratches. For a larger project, use a sander if possible. This will cover a large area more quickly than regular sandpaper. If the area is small, sandpaper will be more efficient. The grit of the sandpaper is an important factor. The lower the grit, the more abrasive the paper will be. If you have deep scratches, around 120-grit sand paper would be suitable. If you have small scratches, which is why you may wish to buff the aluminum, around 400-grit sandpaper would work well.
Move your sandpaper or the sander over the area. Use an even back and fourth motion in a small area. Once that part of the aluminum is buff, continue to a new location until the aluminum does not display any more scratches.
Examine your work. Look closely at your buffing technique. The scratches should be gone altogether or with only light marks remaining. If scratches are still present, go over that area once more with the sandpaper or sander.
Use an aluminum polish product to polish the aluminum. You can find this product on the Internet or in some stores. This polish is for aluminum and metal-based areas. When you use polish, be sure to read the instructions and check to see if it is safe on aluminum.
Take a soft cloth towel and dip it into the aluminum polish. You will not need a large amount to shine aluminum. Rub the polish into the aluminum with a circular motion. Begin in one area and polish each section at a time.
Use the second soft cloth towel to rub the area you have just polished. This will remove any excess polish left on the aluminum and rub the rest in for a perfect shine.
Repeat Steps 2 and 3 until all of the aluminum area is polished.