cleaning a tiara

My sister is lendign me her tiara. It is beautiful and was custom made. Question- what do I use to clean it? its make of sworovski crystals. It needs a little boost of shine.. anysuggestions. i was going tp bring it back to the designer to clean it but he is too far and is charging me $25 to clean. no thanks. I just dont want to use something that might tarnish it.