Drano is a chemical drain-cleaning agent that is primarily used to clean out interior pipes and plumbing apparatus. Drano is primarily based on sodium compounds, including chlorides and nitrates, to make it the most effective. However, cleaning the interior pipes and plumbing is only one of the uses that the handy homeowner can use Drano for. In fact, Drano's chemical composition is set up so that it can clean any type of drain, including outdoor gutters.
Flush the gutters out. This is just a quick rinse job that you should not spend much time on. Simply use a bucket of water or a garden house to clear out all of the loose residue that could prevent the Drano from doing its job. It will also loosen up leaves and other rubble from the gutter. Ideally, your gutters should have guards on them to prevent the concentration of a lot of leaves and rubble. If this the case, proceed to step three.
Clear out the leaves and other rubble from the gutters. This can be tedious and time-consuming, but this kind of rubble will prevent the Drano from doing the best job. Though the Drano will help clear out the rubble, it will most likely not get the bulk of it if there is a lot in the gutters. If you want, you can use the Drano first and then go back to the gutters and clear out everything that is left.
Pour Drano into the gutter. It should be at the farthest possible point from one of the drains to maximize its use. You will have to pour it into several different spots along the gutter. You should use about one fluid ounce per foot of gutter for the best effect. For maximum effect, use one fluid ounce per six inches of gutter.
Rinse out the gutter again with water. This will clear out all chemicals and remaining debris from the gutter, leaving it cleaner and shinier. Once this is done, you will have better functioning gutters that look much better and will last longer.