We introduce a new parameterization of four-fermion operator matrix elements which does not involve quark masses and thus allows a reduction of systematic uncertainties. In order to simplify the matching between lattice and continuum renormalization schemes, we express our results in terms of renormalization group invariant B-parameters which are renormalization-scheme and scale independent. As an application of our proposal, matrix elements of Delta I = 3/2 and SUSY Delta S = 2 operators have been computed. The calculations have been performed using the tree-level improved Clover lattice action at two different values of the strong coupling constant (beta = 6/g(2) = 6.0 and 6,2), in the quenched approximation. Renormalization constants and mixing coefficients of lattice operators have been obtained non-perturbatively. Using lowest order chi PT, we also obtain (pi pi\O-7\K)(I=2)(NDR) = (0.11 +/- 0.02) GeV4 and (pi pi\O-8\K)(I=2)(NDR) = (0.51 +/- 0.05) GeV4 at mu=2 GeV.