Swappable Cup

Solution

Why do we use paper cups?

Carrying around reusable cups is awkward and inconvenient, and they often cost very little or nothing more than drinking from a reusable cup.

What if, instead of making disposable cups to replace them, we could find a way to make reusable coffee cups travel for us?
This idea is that rather than carrying a reusable coffee cup around, people should be able to deposit them anywhere, earning a small incentive in return. 

Every chain of coffee stores should use the same 'swappable' cups which a consumer can take away for the cost of a dollar or two. Rather than carrying this cup around, or throwing it away, the consumer could return to any other caffe or participating shop and return the empty cup, regaining the extra dollar spent.
As there are cafes everywhere, the 'swappable cup' could replace the standard disposable coffee cup causing no extra inconvenience to the user. All they have to do is walk into the nearest cafe as soon as they have drunk their coffee, and return the cup. The cafe then washes the cup and gives it to the next customer.

Waste Reduction

Because no one would need to use disposable cups, waste could be reduced to zero! As long as the consumers return each cup, the cups could be continually reused.

Resources Required

Of course, in order for this idea to be effective many different coffee shops need to join in. Once a company like Starbucks begins, it will become easier for the other small cafes to join in. The plastic for the cups would be the main physical resource required.

Other Advantages

This would encourage consumers to walk into a variety of coffee shops, helping them to remember and notice cafes and helping boost competition and demand.

New Approaches

Machines could be invented which accept a cup and return a dollar without a barista intervening. This would allow 'cup swappers' to be placed throughout cities and shopping malls, increasing convenience for consumers.

If many different cafes join in, and the supply of reusable cups is restricted, the 'swappable cup' could become very widely used.

The cafes would have to agree to all use the same standard cup, and not to print or engrave logos in the side of the cup so all of the cafes will accept them. Each cafe could possibly have a removable paper band that fits around the cup advertising the company.