Try to increase the attenuation distance for example. This will help to get rid of the muddy appearance of your liquid. Attenuation distance controls how far a ray may travel before it looses its energy. A higher value will thus result in a clearer/less tinted liquid.
cloudy? the sprite looks nearly dead-on, good job
now why are the cans still un-opened?
edit: I think I see what you mean now, there should be a bit of the can showing through the sprite/glass…maybe the geometry of the glass is too much and refracting the can in a way that makes it disappear??