The invention relates to a protective cap for closing a connector for containers containing a medical active ingredient, to a connector system, and to a method for cleaning and/or disinfecting a surface of a recessed diaphragm of a connector. The protective cap (1, 1) according to the invention comprises an outer cap region (2) and an inner cap region (3), wherein the outer cap region (2) and the inner cap region (3) form between them a substantially annular hollow space (4) for the engagement of an annular connection piece (21) of a connector (20), wherein the inner cap region (2) has a pad (5, 5, 5) for cleaning and/or disinfecting a diaphragm (23) of the connector (20), which diaphragm is recessed with respect to the edge (22) of the connection piece (21).
