Can you describe the odor? If it is an electrical odor, it could need to have the carbon brushes replaced. If it's an odor from something that's been sucked up, other steps may be necessary. I have a Oreck BB mini vac that had an obnoxious dog odor when running. I solved it by removing the bag and spraying lavender scented Lysol (Generic Walmart version, actually) directly into the hose with the machine running until the scent lilacs started emanating from the exhaust, which took about 10 or 15 seconds. I then stopped spraying, but kept it running for a couple of minutes. When I was satisfied the odor was gone, I put in a fresh bag and called it done. Thus far, the dog odor hasn't returned.