Switching wire brushes can help achieve greater efficiency
Amazon.com: Wire Wheels for 4 1/2 Angle Grinder, 4&3 Inch Wire Wheel Brush Cup Brush Set, Wire Wheel for Angle Grinder, Angle Grinder Wire Wheel for Heavy&Light Duty Work, 5/8 Inch 11
Amazon.com: TILAX Wire Wheel Brush Cup Brush, Twisted Knotted Cup Brush for Grinders, 5/8 Inch-11 Threaded Arbor, 0.020 Inch x 3 Inch for Heavy Cleaning Rust, Stripping and Abrasive, for Angle Grinder :