format USB stick

how do I clear off old data and re-format a USB device in OS 10.7

Open Disk Utility (Applications => Utilities). Select the Flash drive in the left pane, click the Erase tab in the right pane, select the format (usually MS-DOS) and click Apply.

G'day and welcome to the forums.

If you are going to use it exclusively with your Mac, format Mac OS Extended, otherwise as cwa107 suggests.

thank you. It cleared off, but now as I scan to the USB, it said it was empty.

Yes, formatting a disk wipes it clean. This is normal behaviour.

okay, I scanned new material onto the USB and could read it. Then I scanned more of the same and the flash drive said it was removed from the scanner. I am running the repair disk utility now. May have to start over. Good thing I didn't immediately shred the documents I was scanning.

How are you scanning content? Are you telling the application to save the scan to the USB drive? If so, the files should be on the USB drive and depending on how you've set up the scanning application, it may or may not also be on your computer somewhere. Is this what you mean by "removed from the scanner"?

I have an HP Officejet that can be set up at the computer or at the printer to scan to memory device that is plugged into the printer. I plugged the USB flash drive into the printer and piled the copies on the auto feeder on top.