Please sit in the morning to perform havan. Havan must be in sunlight then it is more beneficial. Then half a bowl of fresh water with a tablespoon must be with you with small twigs specially of mango tree if possible. Havan samagri, ghee, camphor and match box must be there with you. Please sit on such asan on four time folded blanket and blanket must be on mat. Sukh asan i.e., sit on duly folded feet in comfortable position. Then first close your eyes and concentrate between two eyebrows and chant Gaytri mantra three times within heart and not by mouth.
Then open your eyes. Take one spoon of water in right palm. Chant this mantra, OM AMRTIO UPASTRANMASI WAHA and drink the water put in your palm. Then again take the spoon of water in right palm then chant the next mantra, OM AMRITA APIDHANMASI SWAHA, AND DRINK THE WATER. THEN AGAIN TAKE THE water in right palm and chant the mantra, OM SATYAM YASHAH SHRI MAYI SHRI SHRAYTAAM SWAHA, AND drink the water. Then wash the right palm while sitting, with the same water kept in bowl.
Then put the twigs into havan kund with one piece of camphor and burn it. During this process chant the Gaytri mantra again and again till such time the fire is lighted sufficiently. Then chant the Gaytri mantra and at the last add the word Swaha and offer ghee with tablespoon, quantity equivalent to 4 to 5 drops. And if you are alone then also offer in fire pinch of havan samagri from your right hand's finger and thumb avoiding forefinger. So this offering may be of 11 times, 21 times or 51 times as the time suits.
The havan with Ved mantras are always offered as the best worship of God only please. Do havan daily and both times.
BENEFITS OF YAJYEN:
Yajurveda gives knowledge to do pious deeds. The first mantra of Yajurveda (1/1) says that human beings must perform Yajyen in which offerings are put in burning fire with Ved mantras. Then mantra says it will prevent the infectious disease and will give constant pleasure. Saamveda mantra 534 says that the matters like ghee and samagri when poured in fire while performing Yajyen, then these matters go in sky and create rain and make the atmosphere pure. Saamveda mantra 536 says that in YAJYEN, the matters (aahuti/offerings) goes up to sun and gives strength to sun to cause rain. Saamveda mantra 537 tells the offerings in a Yajyen must touch the ray of light of sun. Saamveda mantra 539 says that the offerings in a Yajyen, goes to the sky to create rain so that the animal, birds etc., are increased in number. Saamveda mantra 1379 says that Yajyen must be performed while chanting ved mantras and mantra 1380 says that age is increased by Yajyen. Saamveda mantra 1363 says thatone who loves Yajyen, he well concentrates/meditates. Saamveda mantra 1270 says that the offerings in Yajyen goes in the sky through ray of light of sun. Yajurveda mantra 1/2 says that Yajyen purifies the earth. It is stable in ray of light of sun and goes to sky and sun through air. Yajyen purifies the air and holds the universe spreading pleasure all over. When Yajyen is performed then air touches the burning fire and scientifically is purified just as water is boiled on fire and becomes purified. Then the pure air goes up and the old air starts touching the fire and after becoming purified goers to sky and this procedure is continued till the end of Yajyen. Yajyen is basically performed by using a stick of mango tree.
A scientist named Trelle of France did experiments on Yajyen. He found that Yajyen is mainly performed by using mango tree. When the wood is burnt then a gas, "formic aldehyde" comes out which destroys the harmful bacteria and makes the atmosphere purified. Then only, the scientists made "formalin" from "formic aldehyde" gas. He also did experiment on jaggery Gur (in Hindi raw sugar) and found that on burning the jaggery, jaggery also generates "formic aldehyde" gas. A scientist named Tautilk came to know that if we stay in a Yajyen and its smoke for half an hour then the germs of typhoid are destroyed and all these matters are used in Yajyen. Yajurveda says that four types of things mainly used to prepare offerings for aYajyen- 1. Sweet Like honey, jaggery, raw sugar etc., 2. Antibiotic herbs like gyol, etc., 3. Nutrition like pure ghee, dry fruits etc., 4. Fragrant materials like elaichi (cardamom) dried petals flowers etc.
So when all these are offered then it happens that when a household lady in her kitchen fries chilly in ghee then you know the effect of the chilly through air even goes to a far distance like drawing room and other rooms too. So is the case ofYajyen and similarly the offerings of all the things goes to the sky and to sun making contact with air and ray of light of sun. chilly leaves its bad effect to the nose whereas the above said things used in Yajyen leave the best affect in atmosphere according to the qualities of each thing. That is why Saamveda mantra 3 says that burning fire is like messenger/ambassador which does work to carry the effect of all above things to the sky i.e., spreads. Everybody knows thatthings/matters are never destroyed but changes its shape only. There is also a misunderstanding that in a Yajyen/havan carbon dioxide gas is generated. Carbon dioxide is available in whole of universe. Its huge quantity is harmful only but when carbon dioxide comes out from havan, duly mixed with ghee and other things it becomes beneficial to all human beings. Secondly inthe mango tree, not much carbon dioxide comes out while burning. Scientists also say that carbon dioxide is taken by human beings in soda lemonade which becomes digestible. Therefore the holy Yajyen in addition is a scientific action which is beneficial to the whole universe.
Dr. Kundanlal (M.D.) was an allopathic doctor, he took twelve test tubes made of glass duly purified scientifically , six sets of two test tubes each made and each set was filled with milk and food i.e., six were filled with milk and six werefilled with food. In six test tubes, there was air of Yajyen/havan. In other six test tubes there was only ordinary air of garden filled. Now Dr. Kundanlal started regular watch on each test tubes. He found the result that the food which was filled by ordinary air of garden started decaying and giving bad smell quickly whereas the food with air of Yajyen/havan started decaying slowly. This experiment was based while performing a single havan but a spiritual havan containing all things (minimum 21 herbs) will give the best result.
Therefore there are unlimited benefits of Yajyen which can not be explained in full being much lengthy. I have forgotten about an article I read in a leading newspaper of Indonesia about ten years back, in which it was mentioned that in a country, a jungle up to the area of 30 miles started getting dried up due to a disease in herbs and trees. The Govt. tried level best to nurse the jungles but all in vain. The country came to know from somewhere about Yajyen and not Yajyen buta simple havan without Ved mantras was started there and slowly, the whole jungle was recovered and became greens, duly free from disease.
Yajyen in the night will contain only spiritual effect but the physical effect for causing rain and purification of atmosphere will be decreased as all the things used in Yajyen/havan will be unable to go to sky and even to sun in the absence of ray of light of sun as mentioned in above mantras.