Keep them if your single and straight, the chicks will love to see you in them while you bend them over the bathroom sink, kitchen table or front room sofa, if your a garage dweller, over the hood of your classic car.
You can always keep them so your girlfriend gets jealous, you can tell the truth that they were a gift, but she wont believe you, so the mystery could play in your favor as she tries to prove she gives a better BJ then the phantom mystery lady.
If your a #$%$, well then its a no brainer.
If your even thinking about being a #$%$, again. no brainer.
If your #$%$ a phobic, throw them in the fire ASAP. Better yet, get yourself a #$%$ and throw him and the socks into the fire, wait did I just say that? OOps its a hate crime, so theres special mandatory prison terms if your caught, so make sure you do a really good job and don't totally destroy the smoldering socks.