Elena Demonai, as the cuffs' crafter, eventually removed them at Marisa Pines Camp, along with the magical protection the cuffs provided Han. However, doing so also freed his latent powers, returning to him the ability to cast his own magic. It is notoriously difficult to place them on a member of the Waterlow House because of their immense magical power, and the task is completely impossible if the wizard's magic is allowed to mature. If the cuffs were placed at birth and taken off later, it would then be impossible to put them back on.
There is another type of magical cuffs similar to the silver cuffs known as the magebinders. However, while the silver cuffs are designed to absorb any and all forms of magic, the magebinders are designed to inflict pain on their wizard prisoner and, with time, condition them to their captor's will.