Preheat the oven to 350 degrees F (175 degrees C). Rinse the turkey legs and pat dry.
Stand the turkey legs upright (as if the turkey were standing). Press a knife downward into the deep tissue, creating 2 or 3 long pockets. Press a piece of celery into each opening. Pull back the skin on the legs, rub with butter, and season with a little salt. Put the skin back into place, rub with more butter, and season lightly with salt. Lay the legs in a roasting pan.
Roast uncovered for 1 1/2 to 2 hours, until the legs are golden brown and the internal temperature is 180 degrees F (82 degrees C) when taken with a meat thermometer. Add more water if needed while roasting, and baste occasionally with the juices or butter.
