The Issue
You’ve inserted a drawing into your drawing. After doing this, you realize the file is gigantic due to the extra line types and other objects that were inserted. You then run purge multiple times, yet the line types are still there.
The Solution
1. Open the Layer Translator in the file that you are having an issue. The layer translator can be found on the manage tab.
2. Under the right hand box, choose the button "Load..." browse to the same file you have open (the file you are purging line types) This is the illogical part, but the Layer translator only brings with it the actual layers and settings that have been set in the manger. The extra line types not being attached to any specific layer are left out.
3. Once Layers have loaded select "Map Same" button in the middle of the two upper boxes.
4. Once the layers have been mapped they will show as having disappeared from the left hand box and all the layers will appear in the lower box. Select "Translate" button at the bottom.
7. Run the audit
8. Purge all again.
9. Type in LT to pull up dialog and confirm that all excessive line types have been removed.