Abstract: A brush device comprising a plurality of tubular units arranged in alignment and a cap to construct a column externally sealed by a sealing coat. The front end of each unit is provided with a brush head, and the portion around the brush head and the rear end of each unit respectively form the male part and female part of a socket joint, the male part being slightly longer than the female part, thus forming a slot at the junction of two adjacent units radially extending around the periphery of the column, which slot provides a guide to facilitate one to make a cut around this portion to remove an exhausted unit.