uses winrar's -r switch to recurse >1 folder containing >1 zip(s).
all zips in parent have a comment of 0 bytes added to it, thereby removing any comment
start /w %WINRAR% c -y -r -ibck -z%NULL_COMMENT% %DIRNAME%\*.zip
NULL_COMMENT is a null text file of 0 bytes; eg:- 'D:\WUTEMP\Support\pack-com-null.txt'
DIRNAME is the parent folder containing sub-folders of titles and their zips; eg:- 'e:\uploads'
WINRAR is location of installed WinRar program to the winrar.exe; eg:- 'C:\PROGRA~1\WinRAR\WinRAR.EXE'