I've recently started to get some Tiffanys silver pieces and wanted to get them cleaned. They look dull and I want them shiny again. I've never had this done before and have NO clue how it works. First off, is it free? Do we tip? I'm soo noobie and I don't want to walk into their store and look like a complete idiot. Any advice on how I would approach this? Have any of you done this? How was the experience? TIA!