Old Bone China 'crazes' as the bone dries and contracts and the glaze on it cracks slightly, and this is especially the case with old English China. To help stop this from happening, or getting worse, if you store your china in a china display cupboard, put a small cap full of water in the back of the cupboard to ensure the air remains humid (and top up as needed). If your china is displayed on the wall or in the open, instead of dusting it, occasionally hand wash it gently in warm water (you can line the sink with a hand towel before filling it to ensure your delicate china is protected). Also, never use sprung plate holders to hang old china, as the pressure placed on the plate over time can cause it to crack.