To Purge Unneeded Blocks, Layers, and Style Definitions
Use the Purge dialog box to delete unused block definitions, groups, layers, dimension styles, linetypes, text styles, materials, and other objects from the current drawing.
To purge text styles or other unreferenced styles, use one of the following methods:
To purge all unreferenced text styles, select Text Styles.
To purge specific text styles, expand the Text Styles tree view. Then select the text style definitions to be purged.
Note: If you do not want to confirm each purge action, clear the Confirm Each Item to Be Purged option.
Click Purge Checked Items.
Note: If you want to purge an item, but can't find where the item is being used, click the Find Non-Purgeable Items button at the top of the Purge dialog box.