Thank all for reply,
Well, i think that is important to sign old wallet not only for selling or for loaning. Sign an old message is the proof of identity that confirm you are the same owner of the address since it was staked.
It is true. Can i ask you a question so that i can help you. Do you have same username on yobit and bitcointalk? If you have. You make a video on your yobit account. Start from login until to your yobit wallet address that you want to be verify.