I am a box that holds keys without locks. I can be opened but never empty. What am I?

Category: Brain · Difficulty: hard

Hint: Think about something that creates music.

Answer

A piano or keyboard

Explanation

A piano has keys that are not locks, and while it can be played or opened, it produces sound and music, thus never truly being empty.

This is a hard brain riddle — a tricky one that takes a little thought. The answer is A piano or keyboard.

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