Not sure about the expiry thing but i think the stale smell may
not mean it undrinkable , coz usually the stale smell was formed by
when u open a bottle to drink , ur mouth may have a strong smell or
oily and drink the water , they oil or stench from the mouth will
be carried by the water , or bottle cap , hence , u cap it up , and
usually expose to sunlight , the mini evaporation in the bottle may
cause stale smell to rise , so guess what u smell when u open ur
bottle
