Beautiful Flowery Design

I have a set of these plates (12 pieces), from my mother as a gift for our wedding. The plate is made in China, and its written on the back of it, Kashima, made in China. My mother has owned these plates since she was young, so they are antiques. The plate has 20cm diameter, and is medium-sized, just the perfect size for serving meals, not too big and not too small either. The surrounding is decorated with some purple flowers, its just beautiful! Actually, my mother has other models as well, for they come with various flowery designs for each set. But since I like this one, she gave me this set. We always eat our meals with this plate, but unluckily, this plate wont resist against hot stuffs, so when I serve hot rice (we have rice as our daily meal), the plate started to get some brownish stain over the surface. Since then, I try not to serve hot stuffs (maybe only warm) with this plate. Im afraid that since these are antiques, I will ruin these. But what can I do, for my husband cant eat if the meals are not served hot or warm But overall, I really love these plates.