Rust stains are commonly seen on cookware and utensils that are stowed away or infrequently used. These stains appear as the iron content within these cookwares are oxidised over time. The concern most people have is whether accidental ingestion of such stains will affect our health in the long run.
Based on the chemical content alone, consuming a small amount of rust is equivalent to taking an iron supplement. Unless you are overloaded with iron in your body, there is no known harm in ingesting some rust found on your cookware from time to time, especially when they are present in such negligible amount.
Having said that, one should still try to clean the cookware and utensils thoroughly before using to avoid taking in gems which may be present in dirty cookware. Some gems can be really nasty and make you sick.
