If you have the flexible shaft grinder, I'm assuming it's attached to a bench grinder? Try taking your part and buffing it with a loose cotton wheel on the bench grinder. The important part to remember is, when you're buffing, DIRECTION is the key. The reason you're seeing "lines" or "streaks" in the part now is because when you buff in one direction, it's considered cutting, and when you buff in the opposite direction, it's considered coloring. Right now probably what you're getting is a mixture of both. When you go back in the opposite direction from your last stroke, you're cutting the surface down a little bit more, which causes the streaks you're seeing. If you buff the part with a loose cotton wheel and make sure your strokes are all going in the same direction, (to color, you'd go with the wheel), it's alot easier to get an even tone to your surface. The loose cotton wheels are going to cover a larger area with each stroke. Also, as much of a temptation as this is, don't move the part in a circular motion. With a little patience, the surface should even out. Hope that helps.
