A method for making a two component device where the two component are in separate containers with one container inside the other. The method includes placing a first container between the top and bottom of a second container in a die that draws a vacuum between the top and bottom of the second container when they are sealed to form the container. The vacuum preferably ranges from about 8 to about 13 psi. The two components are selected to react to achieve a result, such as the generation of heat.