The Tripuṇḍra shall be applied upto the forelocks by women. Brahmins and widows shall apply the ash also. Similarly it shall be applied by persons of all Āramas. Thus it bestows salvation and destroys all sins.
ब्रह्मचारी गृहस्थो वा वानप्रस्थोथ वा यतिः । ब्रह्मक्षत्त्राश्च विट्शूद्रा स्तथान्ये पतिताधमाः ५३ ।
Whether a Brahmachari (celibate student), Grihastha (householder), Vanaprastha (retired individual), or Yati (ascetic), or even if one is a Brahmin, Kshatriya, Vaishya, Sudra, or any other fallen or degraded being, all can be uplifted through the practice of devotion to Lord Shiva.
उद्धूलनं त्रिपुंड्रं च धृत्वा शुद्धा भवंति च । भस्मनो विधिना सम्यक्पापराशिं विहाय च ५४ ।
By properly wearing the Tripundra (three horizontal marks) and applying the sacred ash (bhasma), they (devotees) become purified. In this way, by following the prescribed rituals, they remove the accumulated sins and become free from the burden of past misdeeds.
A person regularly applying the ash (bhasma) is freed of the sins of slaughter of women and cows and that of heroes and horses. There is no doubt about it.