It's probably more due to build up of some dirt/debris/salt. Start by cleaning the shaft really well - even using a mild scrub pad or bronze wool. Do the same to where it inserts and/or anywhere it slides "through". Keeping it clean should really be all you need. Using a metal polish like Flitz would help, too. Other than that, it's probably best to avoid a lubricant since that will attract dirt. But after cleaning/polishing, if you're still having issues, look for a dry, spray on lubricant like teflon or graphite.
