I made a small fortune selling clothing at my garage sales. I just spread out blankets on the ground, made a huge pile of clothes and let people pick through it. Didn't wash it, didn't fold it, just put it in the pile as is. 50 cents - $2 per item.
I didn't sort through it at all, I didn't have time to. I'm sure somewhere along the line I sold some designer clothing for a few bucks but I was concerned about that. I just wanted to move things quickly. Plus, that's probably the reason that my garage sales were so popular, people knew that they were a treasure hunt and they were always going to find a bargain.
I usually made $200-500 on clothing every week. And yes, if you're not selling your clothing, you're leaving money on the table. Selling clothing and common household items can be the difference between making a profit and losing money on a locker.
At the very least, find someone at your local auctions that deals in clothing and sell it to them. Even if you only get $5 per trash bag, it's better than nothing.