The film covered a wide range of techniques, both physical and mental, that were used to extract information.

This mill was probably used to extract gold and silver.

However, this method cannot be used to extract gold which is present in sulphides.

OpenOffice.org is used to extract the text for the search index.

The wood can also be used to extract a dye.

A larger one in the collection was used to extract horses' teeth.

This tool is often used to extract objects from the background.

Image gradients can be used to extract information from images.

Real estate can be used to extract cash from property already owned.

Knowledge of these can be used to extract information about the identity and health of the plants in it.