A sleeve kit comprising a container sleeve and a sleeve cap which may be engaged with the container sleeve to form a sleeve assembly that envelopes a slush container, the sleeve kit including an attachment system to allow the sleeve cap to be engaged with the container sleeve to form the sleeve assembly and then become disengaged so that the slush container may be removed from the container sleeve. The attachment system may be a single-use attachment system to allow the sleeve cap to be engaged with the container sleeve to form the sleeve assembly. The container sleeve may have a set of at least one vent which allows air to move from an open top end of the container sleeve to a space between a bottom of an inserted slush container and a bottom of the container sleeve to facilitate removal of the slush container from the container sleeve.