U could nt use it again,adding more milk & heat it. Boil it If there s lumbs,put in mixi & blend it. See the result. I never had that experience. But instead of putting it in dustbin,give it a try. Wait what others have to say. There will definitely be so many opinions . wait
I also suggest something but not sure as I never had such problem. DRY GRIND THE MAVA AND than Use by adding milk and make Gulab jamun. Same way in Halwa.