Many old thermometers contain mercury, which can cause air and water pollution and affect human health if released into the environment. These thermometers can be taken to your local Household Hazardous Waste Collection site. You can replace them with digital thermometers that do not contain mercury.
Although thermometers are not covered under the Wisconsin Recycling law, many communities and major retail stores have banned mercury product sales. Wisconsin communities that have banned mercury sales are Dane County, city of Racine, and city of Ashland.