"I've never found a cherry pitter that works well. I have to say I was skeptical. We are preserving cherries today and guess what... it works! Even my son said it worked." http://www.simplycanning.com/cherry-pitter.html
Use Wilton round tip (used for filling pastry/cupcakes). Center bottom of cherry over tip and press down until you hit the pit. Flip cherry over and center stem side on tip. Press cherry down until pit pops up through precut bottom of cherry.