Repairs on pieces are almost always more sensitive to cleaning than the original ceramic. Some restoration materials are water soluble, especially if the repair is old. Care needs to be taken to avoid weakening or damaging the repair.
Clean with soft dry brushes (e.g. squirrel or sable, sizes 4-8) to remove loose dust and dirt. If necessary, use a cotton wool swab slightly dampened with warm water and a little detergent to clean around the repair, but avoid the repair itself. Reswab the area with clean water (no detergent) and then blot dry with a paper towel (see Glazed earthenware ).