How to clean rust off battery holder prong things?

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Is there a way to clean rust or whatever off the holder or compartment where the batteries go in electronic equipment? someone gave us an exercise equipment stepper machine and the electronic panel doesn't seem to be working. I put new batteries in but it still didn't work. I looked inside at where the batteries go and there is a bluish greenish rust on the prong things that hold the battery in place. Is there a safe way to clean this off so I can hopefully use the electronic part of the machine? thanks for any advice.