It is generally acknowledged that porcelains, among portable antiquities, boast relatively stable physical and chemical properties. However, porcelains from sea water are likely to suffer from deterioration such as salting out, attachment and corrosion due to the complicated burial environments. In the course of conservation and restoration, some natural diseases are easily mistaken for production defects. In order to preserve as much historical information about the antiquities as possible during the clean-up process, we systematically examined traditional porcelain production methods used at the Jingdezhen Kiln, and conducted further research on typical production flaws that can easily be confused with the natural diseases. Based on these traditional methods and compositional characteristics of porcelains, we provide some guidance on the selection of clean-up methods and repair materials used for porcelains. From the perspective of identifiability and ageing resistance, this paper focuses on discussing the restoration scale of porcelains exhibited in museums. Based on our practical work, we discuss some problems that should be noticed in restoration and also provide an outlook for the future practical work and research.