It is an object of the present invention to collect a scarce metal such as iridium from a light-emitting element which is no longer used. A method for collecting a metal is provided in which an organic metal compound which can emit visible light from a triplet excited state at room temperature is heated, or an EL layer of a light-emitting layer containing an organic metal compound which can emit visible light from a triplet excited state at room temperature is dissolved in a solvent to form a solution, and the solution is heated, irradiated with microwaves or treated with acid water. According to the above method, resources of metals such as iridium or platinum, which are scarce metals, can be utilized efficiently.