Our kitchen and dining room have wooden floors that are looking grubby and scruffy. I think it's a bit of water damage and general wear. We're thinking of hiring a sander and sanding the floors, then varnishing with clear varnish or wax (not sure). We like the pale colour as it is, so wouldn't want to stain the wood. Would this work? Any tips 're product to use? Or should we pay a professional to do a proper job of It? And if so, roughly what would that cost? Thanks in advance.