Reducing ketchup pot waste when eating at a fast food place

For those who eat at fast food places like Mcdonald's or Burger King will notice many of their branches provide ketchup sauce from tiny paper pots such as the one pictured below:

The ketchup is drained from a machine into the paper pot by pushing a lever. Usually when buying anything larger than a small fries, weather McDonald's or any other, you would need more than one paper pot to dip the fries in and finish them.

I usually avoid fast food and occasionally go to McDonald's/Burger King and when I do I use the same paper pot to finish the fries. I just refill it with ketchup when it runs out instead of getting another paper pot and filling it. This reduces paper waste.

I know it won't make much of a difference if one person does it, but if everyone who ate at fastfood places did this, it would make a difference.