If this is a directory that contains files that can be removed after a certain time, and there are no subdirectories where files must be kept.
you could try:
find /path/to/directory -type f -mtime +31|xargs ls -l
If you are sure this lists only files that you want to delete:
find /path/to/directory -type f -mtime +31|xargs rm -f
If you leave out the xargs then you will not get the correct result.
the ls -l would show the contents of the current directory, and the rm command would not remove any files.