In OS X at times you may have an old print job that you cannot delete. It will often say ‘On Hold’ in the print queue.
To clear this out, first open up the Terminal (Applications > Utilities > Terminal )
Type the following, then press Enter:
That will do it!
The cancel command is part of cups. Linux users as well can use ‘cancel -a’ to clear out any stuck print jobs from the queue. (man cancel)