Got Soap? A Volunteer in Peru put together this great tutorial on how to build your own soap dispenser.
Materials : 2 liter soda bottle, 3 liter soda bottle, 1 “closet bolt” or other bolt (1/4”x 2”), 5 of ¼” nuts, 2 rubber washers, Africano contact glue, screw(s) to attach holder to wall. Drill & bit. 
Remove bottle labels and cut off both bottle bottoms. Cut off top of the 3 L bottle, about 2” from cap, so that it creates a 2” diameter hole.
Mount the inverted 3L bottle on a wall or suspend by string as standard Tippy Tap.
Drill a clean 3/8” hole in the center of the 2 L cap. Smooth edges with steel wool or sandpaper.
Plunger assembly: Thread all nuts up to the bolt head, glue one rubber washer to inside of cap and the other to underside of bolt head (or nut), (contact cement MUST be slightly dry before assembly). Slide open end of bolt through cap hole and thread on bolt cap.
Put the cap on the 2L bottle and insert entire unit into the 3L holder.
Fill with liquid soap (thicker the better). You may coat the 2 washer contact surfaces with Vaseline for better seal.
Sanitation Updates 