You may remember the recent scare about trace amounts of mercury in CFLs (compact fluorescent lights), those energy-saving wonder lightbulbs. While the mercury is not a danger in household use, it can be a problem when thousands of the CFLs are improperly discarded and put into a landfill. But now Home Depot has started a recycling program for these bulbs. It will now take back CFLs at all of its 1,973 stores nationwide. Previously, customers had to seek out local hazardous waste programs or smaller retail stores for recycling, leading to a two percent recycling rate. Both Home Depot and Wal-Mart are heavily promoting CFLs, which are 10 times as energy-efficient as conventional bulbs.