The bhasma is symbolic of the ultimate truth, the ultimate truth of all matter. It has a spiritual significance in that it is changeless, immutable like Godhead. It is colorless or white, so to say, indicating purity.
agni is the presiding deity for bhasma. The ash from the sacrificial fire is most sacred. In the absence of it, ash prepared from cow dung is to be used
This is the first thing to be done after “sandhyAvandanam“. Do “Achamana“, take a small amount of “bhasmam” in the left hand, sit facing north, take water in the right hand, chant “Aapohi…” and splash on the face and on the “bhasmam“, repeating three times. Apply the required amount of water in the “bhasmam” while chanting “sannodevI...”.
Chant “Om NamssivAya” and apply the “bhasmam” on
4. right shoulder with right hand,
5. right arm (outside biceps) with left hand
6. left arm with right arm,
7. chest, and then
8. back with both hands, chanting “panchAksharam” (Namassivaaya) every time.
Then, using both hands, apply on the abdomen, both knees, ankles and feet.
Then chant thrishtup “jAthavedase…” and do vyApakam once,i.e.,with both hands, go over the whole body from head to foot, and chanting “panchAksharam“, do vyApakam twice. After “bhasmam” application, the hands are not supposed to be washed, but this condition is usually waived.
In the evening, it is the same, except for dry, single line application (“Aapohi….” not done).