Lynda,
I'm assuming the clothes that are retaining the odors have a percentage of polyester in them; it seems to me that the synthetics have that characteristic as well as retaining grease stains. I've had good luck with Lestoil for both grease and odors in synthetics. If the clothesline method you're using now doesn't work, try soaking for an hour in a warm solution of Lestoil and water, then washing as usual and line drying. Wet garments hold the residual odor of Lestoil briefly, but line drying gets rid of it and the other odors.