Seems there's no way readily obvious method to delete an ad once the item sells. Bugs me to see something of interest, read through a page or two of posts, only to find the item(s) have sold.
I guess the seller should alert the mods when an item sells so that they can delete the ad. Better still, let the seller manage their own ads. Either way would help clean up that part of the forum a bit.
PS: Sorry for the typo in the headline!