While holidaying in Scotland, came across a pair of very rusty needle nosed pliers on the beach. I decided to try out a tip about rust removal - citric acid (present in citrus fruits like lemon, orange, lime, grapefruit) is supposed to be good at dissolving rust without damage to the underlying metal. Soaked the pliers overnight in neat orange squash - works like a charm!
The squash wasn't much good afterwards...
Regards, Tony