The dust is actually some of the foil “left over” after peeling it off the design. You can use a temporary tape (like our purple tape) to gently apply over design and pull off the extra foil or can use a brush to clean up the area.
If you want to use something like painter's tape, we would recommend making it less tacky before putting it on your project. You can do this by using your hands or your pants/shirt and applying and peeling off several times to reduce the tackiness of the tape so it doesn’t tear the project.