Interaction between modified (K,Na)NbO3 ceramics and metallic silver has been experimentally studied to simulate effects of using Ag-containing electrode pastes in multilayer actuators with alkali-based ferroelectric layers. The solubility limit of silver added as an excess component is found to vary in the range of 0.8-2.5 mol% depending on composition and stoichiometry of the ceramics. Inhomogeneous distribution of the residual undissolved silver across the thickness of a single ceramic layer between the co-fired Ag-Pd electrodes is evidenced by X-ray diffraction. The overall effect of Ag as excess component on temperature of the orthorhombic-tetragonal phase transition is found different from the known effect of Ag as alkali substituent.