Weird idea: It just occurred to me watching youtube videos of paint shakers.. that for something like a Vallejo 17ml paint bottle or a 200ml primer bottle, you could maybe just use a 12V computer fan running off your computer, and somehow.. attached the bottle at the center, thus, the bottle should start spinning around and hopefully move the agitator ball you probably put inside. Good idea or not? 😄

Or, create this special "drill bit" for your drill that only required the drill bit to hold onto a bottle, and then you could have the bottle stand out from the drill (more like stirring and not shaking), and you effortlessly squeeze the drill button, to see the drill spin up and down moving the agitator around.