Oooh, that's a good idea! There isn't in the current implementation but I'll definitely consider it for the next version.
I haven't had a chance to make an official announcement about it but I'm going to try to port Item Flood over to a new engine and rewrite a lot of the systems to be more versatile. It probably won't have a release too soon but ideally in the next few months. I'll definitely add more options of when to clear things in that version!