You can try to sell them but you're only going to loose money since most of them will only sell at reg fee. I would say park them, see which ones are getting traffic and clicks. Any domains that can make at least $1 at the end of the month of the parking pages put in one pile. The rest you have to decide if are worth developing or not. Maybe 2 or 3 will be worth development, and the rest are garbage (just let them expire).
Only after you went though that process consider selling any domains, otherwise you will become disappointed from lack of sales. Remember, on average it takes 12 months for a good domain to sell. The only way to beat this time period is to sell the domain off at an auction without a reserve.