rust in buckets

I was stacking the buckets in the barn for the summer and noticed a little rust in some of my older buckets that I bought used. is there anything I can do to stop them from rusting. they were all dried when I cleaned them up after the season and some are still showing a few rust spots. is there anything to stop this but won't affect the sap next year.

thanks

[WESTVIRGINIAMAPLER]

You can sand them a touch to help get the rust off of them and paint the rust spots or the inside of the buckets with food grade paint like they use on tanks! :D