Once the adhesive is softened by the heat, turn off the power. Then use an eraser or rubber cement pickup to roll the adhesive into little balls that can be wiped off with a damp cloth. If the laminator rollers don't have adhesive on them, you can just wipe them off with a damp cloth. If you need something stronger than water, check with your machine manufacturer before using any chemical cleaner on the rollers. If your rollers don't swing out or otherwise offer easy access, clean one part of them, then turn the machine back on and advance the rollers to the next section.
Poor maintenance is a key money waster.
Drytac's Oosterhuis says four out of five laminators his colleagues see in repro shops are in need of some maintenance. What you need to maintain and how often depends on your laminator. If you have an infrared thermometer, make sure it's dusted off. If you have a mechanical thermometer, replace it if it's worn or gets bent away from the roller. Planning ahead is another way to save money in your laminating department.