Bottle Drain

Ever had a little bit of shampoo/conditioner left over that the pump won't reach? How about Ketchup or Mustard that won't drain out of the old bottle? What about other viscous liquids. Here's the solution. Place this device on the "new" bottle that has enough space at the top,
and invert the old bottle on top. It should now sit on a table until all the contents have transferred from the bottle on top to the one below.

To make one specific to your bottles:
Measure the Diameter of the mouth (inside/outside) and the height of the threads. Enter the
radius of the diameters and adjust the Model, render, export STL, generate code (slic3r), print.

The example STL file is for a Large shampoo/conditioner bottle.

This is a very simple OpenSCAD model, 20 lines of code, 46Line including all comments.