Bikram: Can any one other than brahmin do havan?
Swami Ramswarup: Yes, God has given the knowledge in four Vedas for all human-beings who are capable to gain the same. If anybody under the guidance of learned acharya of Vedas learns the Vedic knowledge and havan etc., then he can perform the daily havan.

Omkar: Dear swamiji, pranams. Kindly let me know can a shivling be donated to a pious or sathbrahmin with due vedic rituals. Shivling can be made from anything – gold, silver, parad or mercury, narmadeshwar; sphatik etc.what is the benefit or merit derived from this. Regards. Omkara.
Swami Ramswarup: My blessings to you. Because the worship of shivling is not mentioned in Vedas. Therefore, I am unable to give answer to your question. You may please contact local temple of shiv and ask the pujari about the same.