What compound can one use to produce a commercial for a well-known cleaning powder says that it shakes out white then turns blue?

One compound that could be used is copper(II) sulfate. When initially mixed with water to create the cleaning powder, the white powder would be visible. Upon shaking the mixture out onto a surface, the copper(II) sulfate would react with oxygen in the air to form a blue copper(II) oxide precipitate, creating the visual effect of turning blue.