Barometers Illegal in Garbage & Drains Contains Mercury Household Hazardous Waste Since barometers contain mercury, they are classified as household hazardous waste (HHW) and should not be placed in the recycling bin or the trash. Some communities accept barometers at HHW collection sites and events. Contact your local recycling coordinator to learn about HHW collection opportunities near you. Aneroid vs. Mercury Barometers Aneroid barometers are circular and have a pointer and dial face. These barometers do not typically contain any mercury, even though the unit of measure is inches or millimeters of mercury. For a mercury barometer, the reading is taken from the height of the mercury in a glass column, much like a thermometer. Never Throw Away Mercury Barometers Most antique barometers contain about 4 ounces of mercury that can be released into the environment if disposed of improperly. If your barometer contains mercury, dispose of it with hazardous waste. Ways to Reuse Repair Antique Barometers If you have a broken antique barometer, have it repaired instead of throwing it away. Check out Barometer Fair – they offer restoration and repair services.