I bought 2 food flasks for the kids to take soup for lunch last year but they weren't used much. I took them out today and one smells a bit, sort of a musty mouldy smell. I've washed it out with hot water and washing up liquid but the smell is still there. I think it must have been wet inside when put away. It looks clean but I'm not sure about using it.
Any tips on how to remove the smell and ensure it is safe to use?
Thanks