If you really want them gone due to kids, pets, etc, get 'Cyper WP'. It has Cypermethrin. You mix the powder with water in any 1-2 gallon sprayer and hit any areas where you think they hang out. It kills them in a few minutes and keeps killing for a few weeks. I found several kinds of powdered cypermethrin online, but none of them would ship to SC (or several other states for some reason I can't remember). Cyper WP is the same or better than other brands but is much cheaper. I found it on ebay and they shipped it to SC no problem.
I did the research last summer when my 2.5 year old daughter picked up one of her sand box toys and the biggest black widow I have ever seen fell across her arm and on to the ground. My wife actually had to knock it off of her and wasn't sure at first if it bit my daughter. She called me at work and was so upset (ready to call 911) I had to take the rest of the day off. She put a cup over the top of it because she wasn't sure if it really was a black widow. The rear end of this thing was bigger than a nickel and with legs it was more than 2 inches across. After seeing it, I started looking around and killed about 15-20 within an hour or so. All of them were on egg sacks so I knew that those 15-20 wouldn't even make a dent. After I got the Cyper, I did 3 treatments at double strength in one week (they recommend once every 3 months for spiders). A week after that, I couldn't find one spider, or bug or ant, or anything. I have done 2 treatments this year already. I hate killing all these bugs, but I don't have any choice with small kids. If it wasn't for them, I wouldn't even bother. When they get older and more aware, I will stop spraying.
Tom
Edit: This stuff will kill fish so if you have a pond or anything like that, beware.....