Have you used a device similar to this one (image, below)? If so, you know what it is. If not, you can probably figure it out. I used one for 1.5 - 2.0 hours, today. Happy to be done with it - at least, for the moment!
Addition of 6/2/2015:
Here (photo, below) is the product of my having spent 45 minutes picking cherries, 90 minutes washing and pitting cherries, and about 20-30 minutes cooking them up enough to kill the enzymes and pouring them into jars. Note that there is plenty of space left in each 1-quart jar and that the jars are frosted. Instead of taking the time to process everything for canning, I froze the cherries.
This (photo, below) is the bountiful little North Start Cherry tree from whence came the cherries. BTW: I didn't pick even half of the cherries. I lose interest rather quickly. Last year, the birds got them all - I wasn't in town to do any picking.