The batteries must be disposed properly, because if they start to decompose, they can contaminet groundwaters. The batterys used in watches (Button type), are considered very toxic, and if this batteris end up in the trash and reach the groundwaters, they can contaminate 600.000 liters of water   Materials: Disposable Bottles Batteries and Batterys water to fill the bottles   1- fill the bottles with the batteries ou batterys inside, and once you have a "nice" ammount, fill the bottle with water and them bury it The water absorbs the acid of the batteries and avoid the contamination of the groundwaters. Lets help, and care our plane, not for you or my, but for our kids. Lets be socialy responsables, lets start today