Wash all the suspect materials in a mild solution of shampoo. Hang or layout on newspaper to dry. The materials will smell better, be softer to use, and be shinier. (No kidding!) If you use a bucket or laundry tub for the washing you will be surprised at the amount of grit and oil you will remove. Once when washing a pheasant skin I ended up with about a tablespoon of sand.
Members at the club to which I belong even follow up with conditioner on the squirrel tails - it is hair after all.