If you've ever had a spray bottle that just wouldn't give up the the last few drops, you'll know how annoying and wasteful it is. Instructables user DIYHacksAndHowTos thankfully has a cheap and simple method to make a spray bottle work in any position.
All you need to replicate this setup is a spray bottle, a small piece of flexible tubing and a few stainless steel nuts. Cut the original spray tube down a little, connect the flexible tubing, and then attach the nuts to the end. Now, when you try to get that last little bit out of the bottle by flipping it upside down, the tubing will fall with the liquid. Head over to Instructables for a complete parts list and how-to guide.
How to Make a Spray Bottle That Works in any Direction/Position [Instructables]