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IF you've never used it, you will be amazed.
We used to use it for the patten, Ciborium, Chalice, Candelabra, Thurible etc.
It's cheap, safe and works like you can't believe nearly every time.
Surprisingly enough, it almost always works like the commercial and will depend on how tarnished the patten is - but I think you'll be surprised how well it works: