Potential slack is an effective metric of circuit’s possible performance improvement. It is equal to the maximal amount of slack that can be potentially used for optimization. In this paper, we first present a new, linear programming-based approach for potential slack calculation. Our method produces an optimal solution with significant runtime speedup compared to previous methods. Then we formulate and solve the problem of global potential slack budgeting by clock-skew optimization. We demonstrate experimentally that the potential slack can be significantly improved by appropriate clock skew assignment.