Closure and methods for placing and removing such a closure

A closure for a liquid container, comprising:

• a plug manufactured from at least partially flexible material with a recess which is arranged at least substantially in axial direction in the plug and which is accessible on at least one side, and
• an operating member protruding outside the plug and displaceable in the recess such that a force exerted by the operating member on the recess in the plug can be modified by displacing the operating member.

A method for placing a closure in a liquid container, comprising the steps of:

• A) placing an operating member in a recess in a plug such that the operating member exerts a limited force on the wall of the recess in the plug,
• B) placing the closure into an entry of the liquid container, and
• C) displacing the operating member in the opening in the plug such that the operating member exerts a greater force on the wall of the recess in the plug, whereby the plug engages with bias on the entry of the liquid container.

A method for removing a closure from a liquid container, comprising the steps of:

• A) displacing, relative to an opening in a plug, an operating member of a closure placed with bias in an entry of a liquid container such that the force exerted by the operating member on the wall of a recess in the plug is reduced, whereby a bias exerted by the plug on the entry of the liquid container decreases, and
• B) taking the closure out of the entry of the liquid container.