1) Some small pieces to a toy were left in our apartment some time ago by a guest that must have stayed by us, but we don’t have any idea who it may belong to
2) A towel was left in our apartment by someone who probably stayed here at same time, but we do not know who it belongs to
3) Someone borrowed tapes from us. They moved to a different country and left the tapes with a friend to return to us. The friend left a bag by our door containing our tapes as well as other random tapes (that don’t belong to us ) and other items that don’t belong to us. We don’t know who dropped off the bag and we don’t know how to get in touch with the person who borrowed our tapes
What should be done with these items?
Also is there a note we can leave in our Guest Room that would absolve us from responsibility of items left in our house? If so what would be an advisable way to phrase it?
For the future, it is certainly advisable to put up a notice, in a clearly visible place, declararing that the management has the right to deal with any property that is left behind as it sees fit.
As for the items you have found, there is no realistic way of finding the owners, and there is no realistic chance that any owner will be coming to collect the items. I don’t know if the bits of toy are worth anything. For the towel and the tapes, the best halachic advice is to write down the value is a “lost property” booklet, with the details of the items in question. Keep the booklet, and deal with the items as you wish.