I have a Gillette Slim adjustable. Its in pretty good condition. I've used an ultrasonic cleaner on it, boiled it, and generally scrubbed it with jewellery cleaner and a toothbrush. Its clean and all works fine. Is there something else that can be done as it still looks a bit dull especially on the handle/grip? Not knowing anything about chrome, could it be taken somewhere and a mirrored chrome finish be applied? Or would that be silly?
I'd try some metal polish on it. I use a polish called Maas, but I would use any metal polish that I could find locally.