The most efficient way to create steady pressure inside a container is to use a compressed gas tank, such as CO2 or N2, rather than initiating a combustion reaction. Using a combustion reaction with hydrogen is not advisable, as it generates high pressure only briefly before condensing into water, which decreases pressure. For maintaining a consistent pressure while minimizing gas usage, compressed CO2 is recommended due to its cost-effectiveness and ease of use. The ideal gas law can be utilized to determine the necessary volume and amount of gas needed. Overall, compressed gas is the safest and most reliable method for achieving sustained pressure.