Ryan has told me in the past that he would rather they were marked sold and left on the site. There is valuable historical information and photos that can help others in the future with parts and car identification. Simply mark it sold, and please do not reply to your ad when you do. that moves it to the top and is unfair to the active ads
I always mark stuff sold but leave up the pics so in case the buyer gets the item and doesn't think it was represented fairly, we have proof. I always over-describe parts I sell, so hopefully there are no surprises on the receiving end.