Fine. Don't get frustrated though because shit happens like I saw this question earlier but didn't have time to answer it.

I used to have a link for a study on UV effects on hair but I can't find it. I don't know how effective it is off hand but yes your method would be helpful in reducing THC metabolites in the hair.

Heat is helpful in many chemical reactions but by itself I don't believe it does anything. Many people will add heat to a bleaching or relaxing process but I don't see many people using it alone.