If your trying to mirror polish then procede on down the line to 1000, 1500 and lastly 2000 grit automotive paper... On a flat plate like that it would be easy to polish to a mirror shine... Wrap the paper around a block and wet sand with the higher grit papers with a back and forth motion... 10 minutes, some elbow grease and a good final buff with Mothers and a quality microfiber towel wrapped around the block (again back and forth) and you'll have a finish worth the shades
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