You can't wash them? Of course washing them would remove the odor. I suppose dry cleaning would too.

Try using some white vinegar in the rinse cycle, that should help alot..

Try putting them in a large zip lock storage bag with a few handfuls of baking soda. Shake the bag and let them sit for a few days. Then run them through a rinse cycle with some white vinegar like Christine1950 advised, followed by a regular washing. I have found that it's best to hang them to dry for all future washings, as the heat from the dryer tends to bring out the odors a bit more.

That method helped salvage some vintage tops from my Mother that my daughter wanted to wear. My daughter said that even after a few washings she'll still catch a faint odor from time to time, but it doesn't bother her.