I just had new hardwood floors installed in my apartment - mainly for resale purposes - but need to protect them from my furniture. I have already got the felt pads to add to the bottoms of chairs, tables, dresser and sofa legs but my main concern are my bookcases. I have several - some very large which will weigh a lot when my books are on them. I have the long skinny felt pads but they really don't look as if they can really protect the floor when the books are all in. Any (in-expensive) ideas of what else to use to put under the bookcases to help protect the new floors - which look amazing at the moment.