I'll take the other gentlemens' comments one further, and tell you that there is an app available at the Autodesk App Store, free, called "Drawing Purge". It started out as a independent third-party app, and Autodesk has now endorsed it. It purges everything that "purge" does, plus regapps AND dgn entities that might have found their way into your drawing. You can itemize what you want to purge and what you don't, and additionally, you can perform batch purges for a whole folder or by selected drawings within a folder. It-is-BADASS...
1.Download it to a folder you choose (You can download it to a network folder, and tell everyone to go get it.)
2. Close cad.
3. Go to that folder, double-click the msi installer, and it installs. End of story.
4. Re-open cad, and it will be under the "Add Ins" folder in your top ribbon. There are two menus - Purge and Batch Purge. Go to batch purge to make your settings. You can change settings for both batch purges (Batch Purge Settings and individual drawing purges (Drawing Purge Settings) separately. Once you have your settings, exit Batch Purge, and click the "Purge" button. Your drawing will purge, and list what it purged for you.
There's more, but it's too long to go over here. Just use it...you'll get it.
Cad Manager/Senior Engineering Technician
Autodesk Certified Professional
Intel(R) Core (TM) i7-7700 CPU
3.60 GHz/24 GB BEAST
Civil 3D 2013/2014/2017/2018/2020