Originally Posted by corky

Rinse might be a better word---to me washing implies soap.
Yes, rinse it all off--the turkey will have absorbed what it is going to by then. Pat the turkey dry really well if you want the skin to brown. Then carefully work your fingers between the skin and the meat to loosen it--get your hands as far in as you can...down the sides and near the thighs and drumstick. Then smear your butter mixture (if you don't want fresh sage you can buy Poultry Seasoning in the spice section) all over between the skin and the meat. You can smear a little on top of the skin too if you have some left over. The butter melts and flavors the breast meat as the turkey roasts.
Don't forget to keep some water or wine or broth in the bottom of the pan while roasting otherwise you will have burnt drippings stuck to the bottom. If you are making gravy throw some onion and carrot and celery around too. You will not be eating these--just used to flavor the drippings for gravy.