No, it's a bad idea.
The term "facebook" is trademarked.
Adding any characters, e.g. letters, numbers, hyphens, to the term does not bring about a name which is trademark-free. Especially where the term "facebook" is very distinct. This you probably know.
So parking/selling a name like that, means that you are benefiting from the trademark holders name.
This is considered cyber-squatting which is highly frowned upon in the Domain Industry.
Short answer: delete/drop the name.
It's just not worth it.
Besides, TM names rarely sell-unless the buyer is a newbie/unaware/tm holder buys it themselves.
But don't count on the latter-they could instead go the legal route and then you will have headaches, sleepless nights, fever, and a sore throat.