Neem oil is a vegetable oil that is more or less pressed out of the seeds and fruits of neem, an evergreen tree in India. This is one of the most important products used in organic farming and organic medicines. Neem oil is normally light to dark brown and is very bitter and smells like peanuts combined with garlic. Factories extract neem oil through many large-scale processes.
Lay a few handfuls of the seeds on the counter and roll over them with the rolling pin. Crush them completely and sit the finished seeds inside the cloth bag. Continue to crush seeds in this fashion until all the seeds are crushed and bagged.
Sit the bag down inside the bucket and pour the water through the inside of the bag. This allows the oils to flow out of the bag and into the bucket. If you find that this will not produce enough oil for you, you can always increase the amount of seeds and water used. To do this, simply double the seeds to 4 lbs. and then double the water to 10 cups.
Allow the bag to sit in a sieve on top of the bucket over night. This will allow the remaining oil to seep out of the bag and into the bucket for collection the following morning. Collect the oil and use as needed.
This method is used in Third World countries to extract the oils for use on crops. It takes about 50 liters (slightly less than 53 US quarts) of the oil to treat an area of 1,000 square meters (about 10,800 square feet) of crops. There are other ways of extracting oil at home, but many include having higher technology machines or using organic solvents. The organic solvents are not healthy to use and the machinery used for crushing and pressing the neem seed is expensive and not worth purchasing for a small scale setup. This water extract is the easiest and most cost efficient way of completely removing the extract. Remember if you are going to use this in a sprayer, it must be strained through a cloth first or it will clog.