Sometimes the pickup-able items can appear in glitchy areas of the game and typically the only way to remove it is to It may be possible to pick it up, usually children pick up things easier but it would require lots of precision and luck!

There was another topic with a similar issue but with a wrapper on top of the fax machine, here. Unfortunately we didn't discover any solutions that did work besides waiting for that random event.

Some people make backups of their families every night just in case something like this should happen as well! If you do somehow manage to get rid of that annoying sock, I suggest looking into creating backups as explained in the topic here.

Good luck!