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.
That being said putting them on ice will not make them ice cold. It will make them about 35F. It takes about 5-10 minutes for 12 ounce cans depending on how warm they were to begin, how many you put in at a time, and if you can get it totally surrounded by ice. Cans cool quicker then bottles as glass is an insulator and aluminum is very good and thermal transfer.