I have heard hanging it in the sun will help kill the odors. Borax and Odoban, not necessarily together, are good too.
I had used too much softener in my clothes and got them to smelling musty. I washed them in a strong Borax solution and rinsed them in Odoban (about 1 to 2 tablespoons of the non diluted solution, can be found at Home Depot) and that worked. Had to do it twice.
Edited to add: I did use detergent too when I used the Borax. Vinegar is also supposed to help.