First, put the glass of chocolate milk directly in the center of a metal bin.
Second, fill up the bin around the glass with lukewarm water, up to the level of the chocolate milk in the glass.
Third, put a clothes hanger in the milk.
Fourth, put the bin on a bunsen burner.
The specific heat of the water is higher, so it will heat slowly while the chocolate milk heats quicker, causing millions of microvibrations which will transfer to the clothes hanger and send out radio waves to other planets.
Point some sort of noise funnel into the chocolate milk and it'll send messages to aliens.
Good luck!
