Dusty Zebra

Story, first published: Galaxy Science Fiction, Sep. 1954

An unseen Trader from another dimension leaves mysterious artifacts in the home of a middle-class suburban family. The family, anxious as most humans to make a buck off these gadgets but totally ignorant of their functions, trades some toy zebras for a miraculous dust collector. The dust collectors sell like hot cakes until the scheme backfires, and dust begins pouring back on this world - it seems the dust collectors had been siphoning off grime into an outraged third parallel universe.

Ewald, Robert J.: When the Fires Burn High and the Wind is from the North, p.64