I agree with Frostrubin, the best way to sell the
cels is straight from you to the collectors. 
You already can see by the replies here, that
there are many people interested in your cels, so
putting scans online and asking for offers or
provide prices sure will get you response.
If then offers are too low, you still can put
those on auction sites.

Well, my especially interested shows: If you own
Video Girl Ai, Devil Hunter Yohko, DNA2 or nice
Key the metal Idol cels, I would love see yours
^^. Feel free to mail me.