[Lee Stewart]

Ever take a close look at a tube of toothpaste and noticed a colored block toward the bottom? Most of the time it’s blue, red, green, or black. It’s not an aesthetic choice by the toothpaste manufacturer, nor is it a hidden signal about the chemicals used to make the toothpaste. Those are two or the more popular explanations. However, these colored blocks on the tube are actually called “eye marks.” They tell the machines on the assembly line where to cut and fold the packaging. Without it, tubes of toothpaste would be attached to one another, making it awfully difficult to apply any to your toothbrush.