Unfortunately, heat sets in spaghetti stains, so if you have put them in the dryer they are going to be difficult to get out. Although it is tempting to wash them in hot water, cold will work better. The only other stain treatment that you haven't already tried would be dry cleaning solvent. You could also try placing the stained item in the sink with cold water dripping on the stain. Leave overnight, with the drips falling directly on the stain. This should loosen the stain.