A hollow container is combined with a burstable envelope retaining a liquid agent. The container is designed to allow a user to open the envelope by bursting or likewise rupturing the envelope while it remains in the container. The design of the envelope provides a predictable bursting location and a lower bursting pressure of the envelope to provide a more controlled release of liquid agent. Bursting forces may be applied in any of a variety of ways just as by twisting or crushing. The design allows for desired use of beneficial envelope materials such as polyester films that are otherwise difficult to rupture.