Traditionally the flattened wire is hammered but you can quickly flatten parts of your wire designs with a silicon abrasive wheel. Hammering with a flat polished hammer will give you a polished surface. Unlike hammering, the wheels remove the metal rather than pushing it flat, so it won't distort your design. To get a polished finish you will need to go through the grits. You don't need to start with the coarse wheel, you could start with fine and see what you think. These wheels can get into hard to reach areas. They do remove the metal quickly and can cause a bit of chaos if you don't have good control of the wheel.