Some empty bottles are simply too good to throw away. Unfortunately, the odour of the bottle's original contents often lingers. You can rinse them out as often as you like, but there always seems to be a residual odour.

 

Mustard is a tried and tested way of neutralising odours. Simply add a splash of mustard to the bottle or container, fill up with warm water and shake well. After rinsing again, the unwanted odour will be gone.