Using SubInAcl.exe, I have scripted SDDL.BAT to determine if your ACLs are only made up of migrated SIDs, so you can delete all the SID-history.

The syntax for using SDDL.BAT is:

SDDL Drive: SID FileName


Drive:   is the drive letter you wish to inspect, like C:.                              SID      is the old SID string you wish to test.                              FileName is the name of the file that will contain file system objects that still have the old SID.
SDDL.BAT contains:
                              @echo off                              If \{%3\}==\{\} @echo Syntax: sddl Drive: SID FileName&goto :EOF                              setlocal                              set drv=%1                              set sid=%2                              set FileName=%3                              set uni="%TEMP%\sddl_unicode_%RANDOM%.tmp"                              set txt="%TEMP%\sddl_txt_%RANDOM%.tmp"                              SubInAcl /outputlog=%uni% /nostatistic /subdirectories %drv% /display=sddl                              :: Convert from unicode                              Type %uni%>%txt%                              if exist "%TEMP%\sddl.vbs" goto doit                              @echo.dim fso, readfile, contents, objArguments>"%TEMP%\sddl.vbs"                              @echo.dim FullFileName, object, work>>"%TEMP%\sddl.vbs"                              @echo.dim OutFileName, writefile>>"%TEMP%\sddl.vbs"                              @echo.Set objArguments = Wscript.Arguments>>"%TEMP%\sddl.vbs"                              @echo.set fso = CreateObject("Scripting.FileSystemObject")>>"%TEMP%\sddl.vbs"                              @echo.FullFileName=objArguments(0)>>"%TEMP%\sddl.vbs"                              @echo.OutFileName=objArguments(1)>>"%TEMP%\sddl.vbs"                              @echo.sid=objArguments(2)>>"%TEMP%\sddl.vbs"                              @echo.set readfile = fso.OpenTextFile(FullFileName, 1, false)>>"%TEMP%\sddl.vbs"                              @echo.set writefile = fso.CreateTextFile(OutFileName, 2)>>"%TEMP%\sddl.vbs"                              @echo.Do until readfile.AtEndOfStream = True>>"%TEMP%\sddl.vbs"                              @echo.     contents = readfile.ReadLine>>"%TEMP%\sddl.vbs"                              @echo.     If InStr(contents, "+File") Then>>"%TEMP%\sddl.vbs"                              @echo.	     work = contents>>"%TEMP%\sddl.vbs"                              @echo.	     object = Replace(work, "+File ", "")>>"%TEMP%\sddl.vbs"                              @echo.     End If>>"%TEMP%\sddl.vbs"                              @echo.     if Instr(contents, sid) Then>>"%TEMP%\sddl.vbs"                              @echo.       work=
" ^& object ^&
">>"%TEMP%\sddl.vbs" @echo. writefile.writeLine work>>"%TEMP%\sddl.vbs" @echo. End If>>"%TEMP%\sddl.vbs" @echo.loop>>"%TEMP%\sddl.vbs" @echo.readfile.close>>"%TEMP%\sddl.vbs" @echo.writefile.close>>"%TEMP%\sddl.vbs" :doit if exist %FileName% del /q %FileName% cscript //nologo "%TEMP%\sddl.vbs" %txt% %FileName% %sid% del /q %uni% del /q %txt% endlocal