clear DataGrid(c#)

hello i have created datagrid. i made query and write this lines adapter.Fill(dataSet); dataGrid1.SetDataBinding(dataSet , "table"); but now i want to make a new query (i make always new query) and want to see the new results in datagrid but the old data is mix with new data in datagrid , how can i clear the datagrid completely and see just the new results? thanks koby