An adapter for a jar for use with a planetary mixer, the adapter securing a dispensing container having a body and a removable cap, the adapter having a central aperture through which a longitudinal axis of the jar passes when the adapter is inside the jar. When the dispensing container is secured to the adapter and the adapter is inside the jar: (i) the adapter maintains the container spaced from an inner wall and from a bottom of the jar； (ii) a gap is provided between a top of the jar and the container； (iii) a point on the cap of the container extends further from the bottom of the jar than does a point on the body of the container； (iv) the body of the container crosses the longitudinal axis of the jar； and (v) the container extends over more than half the diameter of the jar.
