Macworld Forums: Automatically Delete Old Files in Directory - Macworld Forums

Is it possible to set up a script that executes every day and deletes all the files in a directory older than 1 day?

You can write your own AppleScript to perform the function. You may even be able to create a workflow in Automator that performs the task.

Unfortunately, Automator (at least as of 10.4; maybe it'll be different in 10.5) lacks any direct ability to either select files based on date or to delete files. However, you can use Automator to run shell scripts, so a solution is possible.
I wrote up what I did in this macosxhints.com hint. It's not necessarily for a Terminal beginner, though it's really not bad. There are also some alternatives in the comments, one of which, Hazel, is a pure GUI solution that helps you create actions for folders to run automatically.
Either the linked hint or Hazel should help you accomplish what you want to do.
-rob.

Another solution would be Folder Actions. If you create an AppleScript that checks the date on each file, and deletes those older than a day, you could attach the script to your folder as a Folder Action.