To delete sold items on Mercari, follow these steps:
1- Sign in to your Mercari account.
2- Click your profile picture.
3- Click My Listings in the drop down menu.
4- In the left side menu, under Sold, click Complete.
5- Find the items you want to delete in the list of your sold items and click View Order.
6- Click Remove Listing.
Mercari allows the deletion of a sold item after 14 days from the last status update, which includes rating and communication with the buyer.