User blog comment:AYET/Chapter 748 - Talk about a debt repayment/@comment-24850639-20140521155240/@comment-71.13.82.190-20140521175336

I don't really get how he is going to get them off without the key. As has been hinted, it is near impossible to destroy sea prism stone so Zolo won't be able to cut it. So at some point we are going to have to come back to Violet. Maybe when they get to Doflamingo they can use the cuffs to take away his powers and the bird cage. Law can switch out Doflamingo's heart for the cuffs, making him powerless.