@Joe-Gill How is it better to do it manually, when powershell can do the same identical thing but faster and in mass and without visiting each computer? It’s simple:
Remove-Computer -UnjoinDomaincredential Domain01\Admin01 -PassThru -Verbose -Restart
https://technet.microsoft.com/en-us/library/hh849816.aspx
Only thing to remember is to definitely delete the snapin after you’re done with it, because it’s associated it’ll run every time you image - which would cause problems.