If you have bits of dough remaining, try a presoak in cold or warm (not hot) water. That should work for the dried on dough, but if it doesn't, then you may have to presoak & then scrape off the wet dough with your finger or a brush before washing. Hard to say what the stains are from your description, probably oil or protein. Oil stains need a solvent. Usually it's enough to rub in a very small amount of dish detergent or any number of commercial stain removers prior to the presoak. For protein, try applying hydrogen peroxide to the stain.