You will need a few Q-tips, some rubbing alcohol, and then a lubricant for the following instructions.
Apply the rubbing alcohol on the Q-tip, and clean the bar by swabbing it. Make sure to remove any sticky residue with the Q-tip. Afterwards, apply lubricant to a new Q-tip to swab the cleaned bar.
It is recommended to use a Teflon or silicon based lubricant, but WD40 is sufficient as long as it is not over used during application.