My first suggestion would be a local audiophile club but if you don't get anybody to pick up via this post, you could list them on Freecycle.com. I've been using Freecycle for just about a year & it's an excellent way to get rid of stuff you don't want to bother with.
It's a Yahoo based BBS & can be found in a lot of localities. I just looked up your area & there's one there that's fairly new. Here's the link:
http://groups.yahoo.com/group/FreecycleMyrtleBeach/The link should give you all necessary info.
The benefit to Freecycle is the folks that want this stuff will come & pick it up, so easier than taking to Goodwill.