Clam may be creating temp files and dumping them improperly. The folders of Recovered Files show up occasionally in my machine, too. They've never been more than junk.
These files were a Mac habit long before OS X. OS 9's trash sometimes has a folder of Rescued Files in it after a crash or restart. Rescued Files sounds more serious than Recovered Files, but they're junk, too. QuarkXpress for OS 9 is/was a big-time offender (I still run it, and for all I know, it still does it with OS X). The Quark files are always labelled Temp, and are always blank when opened.