I'd just let 'em expire. 1800+ points is hardly worth fretting over; consider the equivalent value of the same quantity of airline miles. It isn't much.
If you have a friend or family member who rides Amtrak on one of the 1,000-point (each way) corridors, such as LA-San Diego, Boston-Portland, or Chicago-various, you could redeem a one-way award for him/her before your points expire.