There isn't a tool that I'm aware of that's readily available to do that. Your best bet is to run a regular repair.
But really, hints are just a side-issue of a much wider problem and that is the nodes are overloaded. Is your application getting hit with a much higher than expected traffic? The screenshots you posted show that even read-repairs aren't getting responses from replicas. You should really address the overload issue. Cheers! >
