They have machining marks in them even when polished. I remove them. Start sanding with the finest grit you need to remove flaws. This may be 80 grit. If only a few flaws don't 80 grit the entire wheel. If you have something to spin them with it will be faster, I've done them by hand as well, just takes longer. Make sure to remove all previous grit scratches every time you go to a finer grit. Sand at aprox 30 degree angle after changing grits to ensure you remove all the previous scratches. The rear of the wheel can remain 80 grit for the brushed look. sand 80,150,240,400,600,1000. Then polish. Then tape the polished surface off and sandblast the center. I always paint the spokes as it makes them easier to keep clean, Grey,black, silver, what ever you want them to look like. Tapeing them off to paint is the longest part of the whole process. If you can spin them ( brake lathe works well) sanding takes about 1 hour on the worst wheels. Polish about 1/2 hour. Here's the last ones I did (though they are 200 S). The rears came from 1968. I used a lot of 80 grit.
Doug