A PART file is a partially downloaded file from the Internet used for downloads that are in progress or have been stopped. Some PART files can be resumed at a later time using the same program that started the download. PART files are typically used by Mozilla Firefox and several file transfer programs, such as Go!Zilla, eMule, and the discontinued eDonkey program.
If you are using Skype on a Mac and a PART file keeps reappearing, move the file to the trash and make sure it's the only file in the trash. Then, right-click the "Trash" icon, hold the "Command" key, select , and verify that the trash is empty. Now, when you reopen Skype, the PART file should no longer reappear.
NOTE: To resume a PART file download with FlashGet, you may need to rename the extension to .JC.