Lazy Web request: Mac Excel password protect removal

I have an Excel spreadsheet where some (not all) of the cells are "protected and therefore read-only." To remove the protection, it tells me that "on the Tools menu, point to Protection, and then click Unprotect Sheet. You may be prompted for a password." I don't have the password. Curiously, those cells are editable on a PC running Excel for Windows, but I am using Excel For Mac 2011 (v14.1.4). I've done a "save as" but that doesn't seem to permanently remove the Protection. I've seen various ways to crack the password for Excel for PC but not for Mac 2011. Can you please help me?