Cheerwine is pretty similar to cola. I was once taken with the fantasy of having Cheerwine mead. So, I took two 2L bottles of Cheerwine and shook them and burped the cap over and over until the fizz was gone. (No boiling)
I added honey equivalent to 5% alcohol after fermentation (about 10 fluid ounces). I mixed it a little at a time in a 1 gallon jug and found that I need to shake it quite a bit more to release the remaining CO2 and hopefully capture some oxygen for the yeast to breathe.
Point is, beyond removing CO2, I didn't do anything to remove preservatives. However, I did add honey. I don't think the part that was Cheerwine ever actually fermented, because the Cheerwine flavor remained pretty intact. Plus, a little sweetness, too.
It fermented to a little under 5% and was finished after agitating the yeast to encourage it throughout the process. I racked after it settled and bottled it.
The yeast seemed done for. So, I switched gears and pitched some apple juice inoculated with malolactic bacteria!
This turned out to be an amazing success! They tasted great. Just the right amount of sweet for a soda, indeed hard, and it was carbonated perfectly... but it had a use-within range. They carbonated a little slower than with yeast, but then you had about a month and a half before you risk Cheerwine bombs! I almost hit the mark, but there was a little too much malic acid and the bottles began to be hard to open without loosing some.