Burn Away Brush. These brushes are ideal for applying flux while soldering because the bristles of the brush are fire resistant. They can also be used to apply paint, laquer or other materials as the bristles are fine and soft. The brush is 19cm long and approx 2.3mm diameter. Directions for use: Hold the tip of the brush over an open flame and allow the covering to burn back until the bristles are exposed.Take a paper towel or cloth and clean bristles thoroughly. When bristles need to be replaced, simply trim them back and burn off the covering until more bristles are exposed.