Motorists in Duluth and on Minnesota’s North Shore should be aware of tunnel cleaning that begins tomorrow (Sun 5/6) evening and continues through next week. Crews will be brightening up the northbound tunnels on I-35 in Duluth Sunday night and southbound tunnels the night after. They then move up the Shore to clean the Silver Cliff and Lafayette Bluff tunnels on Highway 61 north of Two Harbors. That work will start in the early evening Tuesday and continue through early the next morning. Drivers should watch for work zones and message boards.