Cases containing some struck on their heads? (10)

I believe the answer is:

matchboxes

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'cases' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps you can see a link between them that I don't see?

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for matchboxes that I've seen before include "Where strikers go" , "Small cardboard containers" .)

I've seen this clue in The Independent.

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