To kill two birds with one stone

Simple but effective.

What do you need?
- Empty soda cans, preferably found along the road
- Wild flowers
- Paint spray leftovers

What a bit of paint spray can do to a soda can. I've killed two birds with one stone.
1. It didn't cost me anything.
2. I cleaned up the world a bit by using these cans which I found along the road.

If everyone made such vases, the world would be clean by now.