The mucus that you are bringing up is probably a combination of stopping smoking and also post nasal drainage from your sinuses, even though the CT scans were normal. It is possible that the smell is from mucus that is sitting and turns color and creates the odor. While infection is the most common reason for this, it is still possible that this is from a non infectious process. The blood is not uncommon, particularly in the winter months. A trial of high dose nasal steroids is probably worthwhile to see if this relieves or eliminates the symptoms. If it does not, I would look harder for a site of infection.