Acoustic resonance method using a piezoelectric resonator effective shear moduli measured liquids and their dependence on the degree of purity of the crystal surface. As a criterion of surface cleanliness adopted the coefficient of static friction, which is used for measuring tribometer design Deryagina-Lazarev. Various methods applied surface treatments which give a wide range of friction coefficients. At the maximum value of the friction coefficient of the surface of the vibrating piezoelectric quartz completely wetted by the liquid and the effective value of the most liquid of the shear modulus.