Interest profit is not like pork or wine. It is not possible to distinguish the money earned in a halal way from the unlawful (haraam) profit. Interest profit is haraam only to the person who obtains the interest. If interest were haraam to the people other than that person, using our money on hand would have been haraam, because that money could have come to us as the output of many unlawful activities.
The important thing is to not take the interest and to return it even if we had taken it at first. However, banks do not take back the interest in this time and day. Therefore it must be given away via the methods you mentioned.
The person who gets the money can be troubled with it, if he/she knows that it is interest profit.
Besides, being known that you take interest is not good for you. It is necessary to cover a multitude of sins. Thus, not telling it is much better. Even if you tell that the money is interest profit, it is not haraam to the receiver.