Adhesion of a nano particle on a flat substrate both with and without deformation and also the behaviors of bullet and target particles after collision are simulated using the MD technique. The bullet particle, a low-temperature solid Argon, is modeled by a Lennard-Jones (LJ) potential, and the target particle is modeled by a strong LJ potential. Parameters varied are the size of bullet and contaminant particles, adhesion force between the target particle and the substrate, and the velocity and collision angle of the bullet particle. Removal characteristics are different between weakly adhered and strongly adhered particles. For soft target particles high velocity at small angle favors removal. For hard particles the particle-substrate adhesion is the determining factor, and the ineffective angle is observed. (C) 2005 Elsevier Ltd. All rights reserved.