Bhasm is made by burning of cow dung with the paddy husk overnight. In the morning the cow dung would have been burnt and became ash which are taken out carefully without mixing the husk parts. The burnings are done normally on the Siva ratri nights. Bhasm is supposed to give health, wealth and prosperity.
If the positions of Sun (aditya) and Saturn (Sani) are not in favorable position at the time of birth, wearing Bhasm after bath with chanting of 'Om Nama:sivaya:' will give relief from the doshas. Since Bhasm is associated with Lord Siva, it is expected to protect us from evil spirits and the consequences. It is to be applied by making it wet with water in the mornings; mixing with sandal paste in the afternoon and applying dry in the evenings is the correct procedure.
Applying or wearing the tilak while meditating or chanting mantras on the deity of ones liking will prevent many of the doshas due to the positions of the planets. This will also bring in prosperity. During the time of inauspicious times like immediately after death or birth in the family and the menses time of ladies wearing or applying tilak should be avoided.