I've used Industrial Purple degreaser as a pre treater on clothes before, just on oil stains not entire loads, I suppose you could add a cup of it to a load of clothes, it doesn't damage fabric.
I had a sweat shirt that I spilled about a half a quart of old nasty gear oil on while removing a transmission, multiple washes with tide helped but didn't remove the smell, I sprayed it down with industrial purple and scrubbed it with a brush tossed it in the washer with the rest of my work clothes and it took the smell right out of it. I also hand wash my shop rags (old bath towels and wash cloths) with it and it will take the greasiest, oiliest, brownest, dirtiest rags and get them surprisingly clean.
