Usually there is no shelf near entrance doors, this is a possible solution. This is a simple holder for hand sanitizer to instal near entry doors. The idea came to help prevent the Corona Virus pandemic.
I added hardware holes, but double face tape should work most of the time.
I recommend PETG for this, especially for outdoor installation.
Depending on the quality of your PETG you may need to slow down the printer and/or increase the extrusion multiplier.
I believe 3D printing and design sharing can reduce the environmental impact of product packaging and shipping, save countless hours of engineering time, and accelerate innovation.
...and it is a lot of fun!!!