We study the local and nonlocal optical responses from a cubic-nonlinear isotropic medium - aggregated colloidal silver solution. Nonlinear polarization effects in the pump-probe technique are considered phenomenologically. The inverse Faraday effect, optical Kerr effect, and self-induced rotation of the polarization ellipse in a disordered fractal medium were observed for the first time. The components of the tensors of local and nonlocal nonlinearities of colloidal silver solutions with different degree of aggregation were measured.