After a light rinse we placed them in glass jars along with a "starter" that Sandra uses for making fermented rice. We thought that should give it a boost and start fermentation quickly.
Sure enough, after a few days the action began and bubbles and froth developed. After a week we decided to rack the liquid and separate it from the grape skins. Since we wanted a sparkling wine we decided to place it in soda bottles, since they would withstand the pressure developed during further fermentation and contain the carbon dioxide so we would have the fizz.
We "vented" the bottles daily and after another week racked a second time and had a beautiful product, so nice that we bottled some and gave it to a friend to sample.
We kept the remainder in three soda bottles in the garage where the temperature was about 50 degrees. We expected the fermentation to slow and end within a few days. One day I forgot to vent the bottles. The following evening we were sitting in the family room and heard this loud BOOM. We looked at each other, looked around to see if something had fallen from a high shelf, and then started searching for the source of the noise. Then I thought of the bottles in the garage. Upon opening the door to the garage we were greeted by the aroma of our sparkling wine which was now spewed all over the floor, car, storage shelves, freezer, and yard tools. Thankfully only one bottle had exploded and it split sideways and didn't spray the roof. 
I backed the car out of the garage and hosed it off while Sandra moved the wet bottles and boxes to a dry spot on the floor. I vented the other bottles while she mopped and we called it a night. The next day we washed down the floor and wiped the bottles before replacing on the shelves. We now were short 1/3 of our "vintage" but we are diligent about venting it every night whether it needs it or not!