My mam bottles seem burnt. Any idea if I can still use them?

Has the inside of the bottle melted as well? If yes, then chuck it because chemicals can surely seep through and contaminate the milk. If no, there is a possibility that only the outer layer of the bottle is affected and since the milk is exposed to mainly the inner layer, the bottle might still be safe to use as MAM bottles are BPA-free. However, if it were me, I wouldn't take the risk. I'd also invest in a different brand of bottle. Alot of my friends use glass bottles because of the fear that these melting accidents might happen.