That is a feature which many have been after. I think someone in the LAVA forums wrote a VI which did that, but it involves using unsupported features. The main problem with that implementation (which the author notes) is that is just goes through one by one, and since the wire cleaning process is dependent on all the other wires and objects on the block diagram, simply cleaning them in order is not necessarily optimal. In any event, general advice would be to try to keep things fairly clean as you code, and hopefully you won't have to clean up to many wires individually.
