I got a few antique dinner old china plates from thirft store I heard old china have lead can I eat off of it? Or usefood safe spray paint?
You heard wrong. People are still using very old china and no one has died. At banquets in the U.K. the Queen uses China made 200 years ago. You Americans worry over everything.
Old Man Dirt
China is glazed if it is real china and the pigments have become glass. So there is no risk from the plate unless some one has painted a design on it using paint. If that is the case then trying to protect it might produce other problems. I honestly don't recommend a coating, but if I was going to do it I would suggest a clear urethane type paint.
if you're head of that issue, why did you buy them? i'd reserve them for decoration out of an excess of caution. "food safe spray paint"? never heard of it
I would not spray it, that might just be a mess. In general it is probably safe, avoid heating it in the microwave; here is more: Many of the old glazes used on antique or vintage china contain some level of lead. If your china is highly decorated or multicolored, there is a better chance that it contains lead glazing or decorations using lead. And those pieces of china with decorations atop the glaze rather than beneath the glaze may contain lead. If any of your pieces of antique or vintage china or pottery is damaged in any way (chips, cracks, crazing, etc.), don't use it in the preparation or service of food. Everyone knows that grandmother's china was not intended to be used in the microwave or in the dishwasher, but it is also a bad idea to place that old china in the refrigerator. Storing your leftovers in the refrigerator on a decorated china plate is not good for the lifespan of the antique, nor is it good for you once you re-serve those leftovers. Why? The plate is fragile and cooling will impact its overall condition. Also, lead can leach from china that is hosting foods high in acidity. Thus, a piece of lead-glazed or lead-decorated antique china that experiences a significant temperature change (as with cooling) may leach.