Assemblies, kits, and methods for occluding a vascular vessel, such as a varicose vein, are disclosed. An assembly can include a removable inner member, a removable outer member, and an elongated expandable member positioned in a compressed form between portions of the inner and outer members. To facilitate their removal, one or both of the inner and outer members can include a handle coupled to a proximal end. The elongated expandable member can include a gelatin material or a collagen material that is configured, when wetted, to expand from a compressed first diametrical size to a second larger diametrical size within a time period of 5 minutes or less. At the second larger diametrical size, the gelatin or collagen material can occlude a vascular vessel for a period of at least 20 days without degrading.