Just 1 teaspoon of mercury can contaminate a 70 acre lake. Mercury must be disposed of carefully. Take any mercury CFL bulbs or long fluorescent bulbs to Home Depot or to the Westchester County Household Material Recovery Facility (H-MRF) located at the Grasslands campus at Valhalla. Also, dispose of your mercury thermostats and thermometers at this facility. The H-MRF accepts household hazardous waste, by appointment, throughout the year.