How to break Cappuccino-only loyalty card, we hear? (3,3,7,2)

I believe the answer is:

put the mockers on

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I'm afraid I can't explain this answer.

(Other definitions for put the mockers on that I've seen before include "Broadcast satire show" , "curse" , "Get satirists performing" , "cause it to fail" .)

I've seen this clue in The Independent.

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