It would be a cool addition to the fruit, and more accurate to the manga.
It could be make as a passive, since an actual ability would probably make a bit too much abilities. Maybe allowing it to remove the effect to any player or entity by pressing shift + right click.
Or you could make it an ability wich create a wax key that can only unlock handcuffs.
You can see Galdino doingt it two times in marineford, once to free Ace in chapter 571 and to free Marco in chapter 574. And I think that he also create more keys to open the cells in Impel Down.