Whatever you do, never advertise anything FREE on FB marketplace, no matter how badly you want it gone. "Free" attracts an array of freaks and geeks that is the stuff of nightmares. Put it on for $5 or $10, you'll get about a fifth of the messages and much less likely to get requests for holds, more pictures, "I was first", etc. Somehow, the word "free" turns people into entitled sh!theads.
Tell possible buyers you'll leave the item on the front step, just put the $5 under the mat, everyone gets on with their day. Who cares if you get stiffed, you just want the stuff gone anyway.