White vinegar and warm water work for me. I discovered the vinegar for laundry smells after my son worked at KFC as a cook. His uniforms smelled so bad that he put them in the washer as soon as he came in the door. The vinegar always got rid of the smell. If there were big stains, I added some borax. I often use vinegar as a rinse in my washer rather than fabric softener. The vinegar prevents build up of soap scum and fabric softener gunk, plus my plumber says it is good for our drain. We have city sewer, so don't know what it would do for a septic system.