Nylon Tube Brush, ¾" Diameter

After drilling a hole in the asphalt, it is essential to prepare the hole for the grout adhesive.  First blow the dust away from the hole area, then force air into the hole and blow until no further dust comes out.  Now apply the brush to the hole surface, going down at least 4-6 inches.  Apply fair amount of force against the walls of the hole while moving the brush up and down, making sure to cover the entire circumference of the hole.  Pull the brush out and tap or air clean it every few strokes.  Continue until no dust is vibily coming out of the hole.