You’d be surprised how many specks of things will get left behind when you scan. Be sure to clean your scanner with some glass cleaner and a towel and then wipe with a micro-cloth before-hand. We recommend if you're doing multiple scans at once to take the micro-cloth and wipe it across your bed every 2-3 scans as well just to keep things clean. If you accidentally touch the scanner glass with your hand you'll likely need to get the glass cleaner out again. Scans with particles and smudges make correcting and cleaning up scans later much more difficult.