Removing files older than 5 minutes.

Quickly list files with time of last modification:
# ls -alt

If you need to remove any that have not been modified lately:

1. verify files that will be worked on by running with ls first
2. delete at will without warning

# find ./*.rrd -type f -mmin +5 -exec ls {} \;

# find ./*.rrd -type f -mmin +5 -exec rm {} \;