I have the following in a batch file:
:REMOLDFILES ECHO Removing files older than 14 days. >>%LOGFILE% cd /d %BKUPDIR% FOR /f \"skip=14 delims=\" %%A I
You could use FOR /F SKIP to ignore the last 10 most recently modified entries after sorting by last modified date:
FOR /F SKIP
for /f "skip=10 eol=: delims=" %%F in ('dir /b /o-d *.zip') do @del "%%F"