The disclosure concerns a cleaner (2) comprising a housing (4) configured to be moved over a surface (6) to be cleaned and a roller (8) partially arranged in the housing (4). The roller (8) is configured to rotate about a rotational axis (10) and to engage with the surface (6) to be cleaned. The roller (8) comprises a container (12) for liquid, an outlet arrangement (14) for dispensing of liquid to the surface (6) to be cleaned, and a flow path (16) for liquid extending from the container (12) for liquid to the outlet arrangement (14). The cleaner (2) comprises a flow regulator (18) arranged in the flow path (16). The flow regulator (18) is configured to be activated by a rotation (22) of the roller (8) such that liquid is transferred via the flow regulator (18) from the container (12) for liquid to the outlet arrangement (14).