I left my newly turned crank in the back of my car for a week and there is some rust on one of the journals on the balancer end. What do I do and is it still ok to use it?

 

Oil and emery cloth or even a rough rag. It depends on the extent of the rust. A weeks worth of rust should be able to be cleaned off.

 

after just a week it should just wipe off.

I would not pay for a shop to polish it. It may come off with soapy water and a clean rag. If not maybe take some steel wool to it.

Just be sure to clean it really well with soapy water when you get finished to get the metal particles off of it.

 

Emory cloth is your best bet as it won't mar the finish on the crank. Once you're done get some machine oil and wipe it down and then put it in a plastic bag and tape it shut.