Knead a small amount of dough and make a small thick roti from it. Dont cook it just put it raw in your dish that is oversalted. The dough wil absorb the extra salt. You can even add a piece of coal. Let it sit there for 20 mins then discard the coal.
Put big pieces of potato and boil the curry and remove the potatoes while serving. You can also put a loaf of bread and remove it after some time.