Using Finder, I was able to empty the trash can with the exception of one directory that remains even though emptying trash raises no error messages. After searching around I found quite a few examples for forcing the trash can to empty.
To find out what files are in that directory use ls -a. The -a flag tells ls to list hidden files (aka "dot files"). Remove those files then rmdir can be used. Another option is to simply use rm -rf to recursively delete the directory and all of
The symlink populated a non-empty directory, but the client was unable to see or stat the symlink for the purpose of clearing out the directory before unlinking the directory.
Normally, an rm -rf will remove everything in a directory, recursively, so it wouldn't matter if it's empty or not. In this case, there are some things you might want to check:
In order to remove both a parent directory and a subdirectory of that parent, the subdirectory must be specified first so the parent directory is empty when rmdir tries to remove it.