Murphy's Oil Soap :)
Lori....Magic Eraser works very well on mine. Good luck!
Murphy's Oil Soap.
Here's a post that might help - https://www.hunker.com/13421688/how-do-i-clean-wood-railings
Scrub it with a soft cloth, warm water and Murphy's Oil soap.
Murphy’s oil soap follow directions on bottle to clean it if the dirt is stubborn then add 1/4 cup ammonia