Ok, so a few months ago me and a friend send a whole bunch of smileys to each other in Facebook chat just for fun. I wish I had known at that time how stupid that was. Even until today, every time I open the chat with that contact, the Facebook tab totally locks up when I try to load that chat. It will load eventually after five minutes or so, but it becomes very inconvenient at times.

On Facebook Messenger for Android, there's no problem and the chat works fine.

I'd like to know if there's any way to completely delete a Facebook chat (not archive them) and start over so it won't load the smileys anymore.