Last year I had all my 'proper' jewellery professionally cleaned, and couldn't believe the difference - most of it is quite old, and it got an incredible new lease of life. Today I'm sorting through a big box of costume jewellery, and realised that while some of it is quite nice, a lot of it has that unpleasant dirty metal smell, and it's all quite dull. Is it salvageable? Although none of it is real, it's not supermarket stuff either, so it would be nice to save some of it. Is there anything I can do - or do I need to chuck it and start again?