Now I know what you're probably thinking "it's already wet"? If you thought that you'd be wrong. This 6% reading is actually about as bone dry as you'll ever get on either solid or cored fiberglass using the CT-33. Using this meter any reading between 0% & 15% is considered dry on fiberglass.
Remember this meter is primarily designed for the many different species of wood. It may also be used on man made materials such as fiberglass. You'll need to reference the scale found at the end of this page for fiberglass interpretations/translations.
Contrary to popular belief moisture meters don't actually read moisture. They actually read capacitance. This capacitance reading is then transposed, onto the analog display, into a relative moisture reading.