Deleting Files

I have a .NET application that cleans a trade-area on my server and generates an report, but when the file is read-only, my application throws the following Exception: "Access to the path is denied." But this is only a trade-area, a place which network users use for copying files, so I´d like to delete every files, but the read-only ones are never deleted, I tried changing this file attribute, an then my application deleted the file. But I can´t change every files, so my application has no reason for existence Can someone help me?