Vallejo paints...

.. do you use them?

 If so, do you have a good method for storing them so that they don't settle and thus making them a pain to mix up again for use?

 I have tried storing the pots (?) on their side, or even upside down, but I still can't seem to get a good mix of the liquids inside when I shake them up with some of my paints.

 I have heard of some people putting small ball bearings inside. Does this work?

Has anyone got any tips or advice on getting the full potential of these paints - i.e. to be able to mix them thoroughly?