[Powers] Help Building an Ability

[JCurwen3]

A player wants his character to have the ability to make any one container at a time bottomless. It takes one minute for him to empower a new container, which automatically disempowers the last container.

Some examples: He empowers a hip flask of bourbon & never has to buy that brand of bourbon again (he can keep pouring it out forever out of the flask). He empowers his left pants pocket (which contains his keys & a $20), which automatically disempowers the hip flask or any other previously empowered container, & he can pull it out limitless copies of his keys & limitless $20s.

Not sure where to start.