When he comes to return the desposit, he should give it to someone of the depositor’s household without his knowledge. Similar, when he comes to return any item that was lent to him, or repay his loan. But he can return it to [the depositor’s] wife, because by default she buys and sells in the home, and the husband appoints all his property to her control.
One is obligated to guard the deposit in a manner that is better than he would guard his own property. And even if he isn’t all that careful with the guarding of his own items, with a deposit he must be very careful.
The one who receives the deposit is not allowed to deposit the item in the hands [control] of others — even [people] who are more kosher and trustworthy than he is. Except if the depositor is also accustomed to deposit items similar to these with them.
סִימָן קפח – הִלְכוֹת פִּקָּדוֹן
188: Laws of Deposits
Someone who deposits money by a friend, now in these days that all our jobs are in buying and selling and we all need cash, the norm is that the depositor is willing to have the person responsible will take it out [for his own use] when he needs it. Therefore, he may take the deposit out, and it is with him like a loan — unless the depositor revealed that he did not want it. Such as if he sealed it in, or tied them with a unique knot; then the responsible party may not take it out [for his own use].
Someone who deposits another item [as opposed to the money discussed in the previous se’if], the responsible party may not use this item for his own needs. Even if the item would not get damaged at all by this use, in any case, it would be [an instance of] borrowing without [the owner’s] knowledge. One who borrows without [their] knowledge is a thief. But if he knows for sure that the depositor doesn’t care about it — it is permitted. Although some prohibit even in this [case], since a deposit — even of something people don’t normally deposit — is prohibited, because one who sends a hand to a deposit also similarly [a thief]. And there is [good reason] to be stringent.