Drano is a brand of drain cleaner that comes in liquid, gel and crystal forms. Its purpose is to remove or prevent clogs and buildup in plumbing pipes. Drano is a hazardous chemical and its disposal must be taken seriously. Because Drano is water soluble, the best course of action is to flush it through your plumbing system.
Empty the remaining Drano into a drain. Use a sink, shower or tub drain, or a toilet. Don't use the kitchen sink if it has a garbage disposal; chemicals in the Drano will be dispersed when the disposal is turned on.
Flush the drain with hot water for a few minutes (or reflush the toilet) to make sure the chemicals have been completely flushed out of the system.
Rinse the empty plastic bottle with water and pour the solution down the same drain. Rinse for a minute with hot water to flush out any remaining chemicals. For metal containers of Drano, do not rinse out the remaining contents.
Tighten the lid on the container. Recycle a plastic Drano bottle; wrap a metal Drano container in newspaper or paper towels and throw it in the trash.