Abstract: A flexible body member has lateral fingers arranged upon rotation to knock off substance which has collected on the inner surface of a chimney. A weight is provided at the bottom end of the body member to hold the latter substantially plumb in a chimney when operated, and a spindle is provided at the top of the body member for attachment to power drive mechanism such as a conventional hand drill. The body member preferably comprises a link chain having flattened lateral engaging portions which produce a drive connection from one link to the next without buckling or twisting. In a modified form of the invention, individual lateral fingers are pivotally connected to the body member and pivot upwardly by centrifugal force upon rotation of the body member whereby automatically to accommodate different chimney dimensions and offset portions thereof.