Described herein is a cover for mounting to a door handle (30) comprises two parts (10, 12) configured for mutual locking engagement such that when the parts are brought into mutual locking engagement around a door handle (30) at least a portion of the door handle is substantially enclosed within a cavity (16) formed between the two parts (10, 12). At least a portion of at least one of the parts (10, 12) is coated, impregnated, or otherwise provided with a self-cleaning material. Also described is a push plate device comprising a first plate (72) for fixing to a door； and a second plate (71) configured to releasably attach to said first plate in order to form a composite plate structure (70). The second plate (71) is at least partly coated, impregnated, or otherwise provided with a self-cleaning material so that the composite plate structure (70) presents a self-cleaning external surface.
