Exercise cannot tighten your loose skin, but you can minimize the amount of loose skin you have. If you have excess skin, patience is key as you wait for your skin to adjust to your new size.
A Pepsi takes between 30 and 45 minutes to freeze solid, depending on the temperature it was at before putting it in a typical home freezer. Be aware that most (but not all) Pepsi containers will burst if you keep them frozen for more than 2 hours.
Now I'm curious as to whether different soft drinks have significantly different freezing points or rates of cooling. I froze a two liter of diet root beer in my car in January. It took less than 24 hours but I am not sure exactly how long. It did not explode and the bottle showed no sign of weakening that I could notice.