A new method for desorbing large biomolecules caused by shock wave propagation in a liquid matrix under bombardment with massive, multiply charged clusters provides an extremely soft way of sputtering intact biomolecules with remarkably low fragmentation patterns and a significantly reduced chemical noise background since the low energy per nucleon impacts are insufficient to cause damage both to biomolecules and to the matrix material. Positive or negative cluster beams are formed by electrohydrodynamic spray of conductive solutions of water-methanol, water-glycerol, and pure glycerol by applying different polarity voltage to capillary emitters in vacuum. The beam source is equipped with focusing lens and an electrostatic deflection system for beam positioning. A permanent magnet deflection yoke can be externally mounted for separation of the smaller, larger charge-to-mass ratio, molecular ion component causing target material damage, from the larger clusters in the beam. A theoretical estimation of the cluster charge-to-mass ratio threshold for this damage is viewed as knocking out target atoms from their positions in binary collisions with atoms of the projectile. The model shows that the lowest threshold is caused by heavy atom-heavy atom collisions rather than by collisions involving hydrogen atoms as projectile or target. An experiment performed to verify the theoretical model has displayed a drastic decrease of low molecular noise background when passing the predicted charge-to-mass ratio threshold.