This patent document discloses assemblies and methods for removing obstructive material from a body vessel or other cavity. An assembly can include an elongate inner member, an elongate outer member, an aspirator, one or more valves, and a waste collection reservoir. Each of the elongate members can extend from a proximal end portion to a distal end portion and can include a lumen therethrough. The elongate inner member can be partially disposed in the lumen of the elongate outer member and can be moveable along its longitudinal axis relative to the elongate outer member. The aspirator can be in flow communication with the proximal end portion of the elongate inner member for drawing the obstructive material into or through its lumen. The one or more valves can be configured and positioned to allow obstructive material removed from the body vessel or cavity to be urged toward the waste collection reservoir.