If you just want to get rid of them and arent concerned about getting the most money, most used record stores give cash for used cd's and buy whole collections. Or they usually give you higher amount in trade. Rasputins does this. I used to go to Streetlight Records on Castro ALOT.

But if you want to take the time to sell them on www.half.com you may make the most money that way. I used to have only about 1,200 books and some cd's and dvds selling on there and I used to make an extra 200 dollars every two weeks without even trying very hard. As an "individual seller" you can have up to 5,000 items and not pay taxes. If you have over 5,000 items you have to register as a business and pay taxes. Otherwise it's like a sidewalk sale. The only thing is that you have to keep the collection in alphabetical order so when you get a sale you can locate it and ship it the same or next day. If you slack on response you may get poor seller ratings. You always want to keep your rating high or it could hurt your biznatch. : )

Good luck. If someone wanted to buy the whole collection how much would you want?

Twist and Shout records buys used cds in Denver

they might have an idea or two for ya also

Ebay might be a good place to sell them. I'm sure there are places online that can help.

Here's a couple links

www.recordcollectorsguild.org/

www.gocontinental.com/pgde.htm

I'm trying to downsize my collection a bit -- get rid of some of the chaff in my cd collection -- so I've thought/wondered about this a little myself.

I've thought of three courses of action:
1) Sell 'em all to a local record store. This is the easiest option, but probably also the least return.
2) Sell 'em all on-line. This is the most work-intensive option, but ~could~ result in a high return.
3) Figure out which ones are valuable and sell those on-line. Sell the rest at your favorite local record store. How to figure out which ones are valuable is the big question. You could do research yourself. Or maybe you could pay ($50? $100?) someone from that local record store to survey the collection and tell you which ones are out of print/rare and worth putting on the auction block.