  We demonstrate the possibility of achieving the maximum possible singlet
fraction using a entangled mixed two-qubit state as a resource. For this, we
establish a tight upper bound on singlet fraction and show that the maximal
singlet fraction obtained in \cite{Verstraete} does not attain the obtained
upper bound on the singlet fraction. Interestingly, we found that the required
upper bound can in fact be achieved using local filtering operations.
