Not easy as they're designed as a 'single use' connector.

What you can try and do is remove the insulation carefully with a blade and then squeeze the flattened edges of the crimp with a pair of pliers. This will cause the crimp to open out a little in the centre and allow you to withdraw the wire's core.

Be wary though that the strands often get damaged during crimping and will not be as strong once exposed again and are prone to breaking at the point where they were previously crushed.

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