Repair fine cracks in china plates and cups by boiling them in milk. The milk reacts with the kaolin in china and closes the crack.
Place the plate in a pan, cover it with milk (fresh or reconstituted powered milk) bring milk a boil, cover and let simmer for about 45 minutes.
I have not tried this myself because I do not have any fine china but if anyone else is interested and would like to try it let me know if it works.
I do have an old porcelain tea pot that has some fine cracks in it and plan to try it on this. The tea pot is very large and will require a large pot and a lot of milk for me to do this, not to mention the tea pot is about 45 years old, so wish me luck.
Source: This tip came from my AT&T home page listed under ordinary object, super uses: by Aishia Sultan.