This cleasing technique is very important and very powerful. It is highly recommended.
Obtain a silver spoon, sterling or silver plated. After you brush your teeth, put a little water in a glass, with a very small amount of salt. Rinse the mouth and expell the water. Having washed the mouth, extend the tongue and take the silver spoon, turned it upside down, reach back as far as you can into the mouth and rub the tongue with the spoon from the back forward. Do not scrape the tongue. It can be amazing the amount of material that will come off the tongue, especially if you are not well.
Next rinse the mouth, expectorate, and repeat once or twice more. When finished, wash, rinse and wrap the spoon, using it only for this purpose. You will find this proceedure very invigorating. It allows a large amount of pranic energy flowing over the tongue to be absorbed into the tongue, moon chakra and the astral body. You will find practicing this technique will make your eyes sparkle and your mind clearer. Practice this technique in the morning, and also in the evening, since Kriya yoga is concerned with the dream state.
Any object could be used to clean the tongue, plastic, metal or wood. However, silver as a symbol relates to the moon chakra. The spoon leaves small deposits of silver ions on the tongue which protects the tongue from infection. According to metaliotherapy, certain metals fight infections. Silver, also opens the moon chakra making one more psychic.
Here is an example to illustrate this: take a petri dish which has a culture on it, and drop in a silver dime (or any silver object). Bacteria will grow in the entire culture except in the area around the dime (silver object of choice). The silver radiates ions and nothing will grow. This is true of gold also. Ultizing silver and gold for money makes for a healthier society. People handling it will not communicate diseases.
In this technique you join together the index, middle and ring fingers. Insert them into the throat and rub the tongue and root of throat. Rinse the mouth with slightly salted water, gargel, and expectorate. Repeat this process one to three times. The hands and fingernails must be thoroughly cleaned before and afterwards. Guard against scratching the delicate oral membranes with long fingernails.
The spiritual science of Kriya Yoga by Goswami Kriyananda