It's an umbrella :P
substitute "up" for "open" and "down" for "closed."
What may go down the chimney up but not down the chimney down?
An umbrella
An umbrella could.... but would? doubtful!
The answer to this riddle is "an umbrella." When an umbrella is opened, it goes up a drain pipe, but when it is closed, it can only go down a drain pipe. This riddle plays on the dual functionality of an umbrella in relation to its position and movement in a drain pipe.
Helium
an umbrella
What may go down the chimney up but not down the chimney down?
A chimney.
An umbrella
An umbrella! It can go up a chimney when it's down because it's thin but cant go down a chimney up because its too big!
Smoke
Smoke
An umbrella.
An umbrella
I go in dry come out wet the longer I'm in the stronger I get what am i
I don't get why, but it's an umbrella
An umbrella !