What can go up a chimney down, but can't go down a chimney up?

An umbrella.

Did You Know?

The trick is thinking literally: an umbrella goes 'up' a chimney when closed (folded down) but can't go 'down' a chimney when open (spread up) — it's about the umbrella's shape, not direction! Fun fact: the umbrella's rib design dates back over 3,000 years to ancient China.