Too many disk_use Files

When I log into my Dreamhost site via ftp, there are always dozens of disk usage files that look like this: [font=Courier]disk_use-2011-02-19[/font].

I’ve been deleting them, since I have no use for them. Is there any reason to keep them?

If I do need to keep them, can I put them in their own folder so they don’t clutter up the root of my site?