Is it carpet or wood floor? On carpet I use a flashlight at floor level while running my hand back and forth a section at a time. On a wood floor I use my Nylon broom and go over the whole floor. On soft surfaces, I gently squeeze the surface to see if I feel a poke. As a last resort, I ask my daughter with younger eyes to come help me search. For now, keep the lets out of the sewing room until you find it.