Unfortunately, cleaning sticky messes off the head and throat of a chicken, especially ones with face fluff, is nearly impossible. The best you can do is a warm wash cloth rinsed in soapy suds, and be aware you can't possibly get it all.
Chickens will clean one another sometimes, and a good dirt bath can remove a lot of grime, too.
I've never heard of using molasses for wry neck. Molasses is usually used to clean toxins out of a chicken's intestines since it promotes diarrhea.
How were you administering the vitamin E and molasses? A syringe delivering a drop at a time into the right side of a chicken's beak is one method. Putting the vitamin E on a tiny bit of bread is another. Usually vitamin E is given with a sliver of selenium to treat wry neck. No need for molasses.
