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.
This Quick Clip shows some of my personal experiences with making instant ice using a bottle of water supercooled in a freezer. To get this instant ice effect, I put unopened bottles of water in the freezer for anywhere between 90 to 115 minutes. The water gets supercooled (below freezing), but does not actually freeze because the water doesn't contain enough impurities. When it touches an ice crystal, it turns instantly to ice.