The 4.0.1 version of USBclean for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This Mac app is an intellectual property of Russell Gray. We recommend checking the downloaded files with any free antivirus. The program relates to System Tools.
From the developer:
USBclean quickly and easily removes all those pesky junk and ghost files from your external Windows formatted USB drives. .DS_Store, Thumbs.db, .Spotlight, and trashes files take up precious space, and can cause issues on some devices. Remove them all quickly and easily with USBclean. Configure USBclean the way you want!
You may want to check out more software for Mac, such as TM Error Logger, HDCleanUp or CLIX, which might be similar to USBclean.