I've rented an old farmhouse that has plaster walls (for the most part). I have some items to hang on the walls but have been having problems getting the sinkers into the wall - they have been breaking. One of my racks, I finally just hung with a screw & it seems to be rock solid. I have some shelves to hang in my sons room & the same thing has happened. I now need to patch the hole & try again. Can I just put the shelves up with screws & will they be secure. He's going to use them for a bottle collection. Also, how do I stop the tub from dripping?