First of all, you should take down the feeder from the place where you have fixed it to attract hummingbirds. Make sure you make it completely empty by removing the remaining nectar from its bottom.
Now separate all parts of the feeder in order to clean every part in a perfect way. Cleaning all parts separately will give a proper cleaning to the hummingbird feeder.
You should take warm water and a scrubber for cleaning the hummingbird feeder. Soak the scrubber into the water and then rub it on the surface of all parts of the feeder which will remove everything from its surface and will make it perfectly clean.
You can also use bottle brush instead of scrubber which will make it easier for you to remove any mud or remaining nectar from the hummingbird feeder.
Now you should take 3 tablespoons of bleach and put it inside the hummingbird feeder. Then fill it with the warm water which will help in erasing anything that has firmly attached with the bottom.
Leave the warm water and bleach inside the hummingbird feeder for about 30 minutes which will help you in removing the dry nectar or other elements in it.
You should also use bleach and warm water to clean all other parts of the hummingbird feeder. Make sure you have rinsed all parts of the feeder thoroughly in order to get good results.
After rinsing it thoroughly, you should recheck all sides of each part of the hummingbird feeder to ensure that it has got proper cleansing.
Then refill the hummingbird feeder with the sugary water or nectar and put it at its place in your lawn or yard.