In this work, the parameters for laser ablation cleaning of contaminants deposited by electrostatic attraction on cellulose acetate (OHP) sheet substrates and their analysis by measuring the transmittance of the irradiated surface as a function of the energy per pulse of an Nd:YAG laser were determined. The energy was controlled by the Q-switch delay time using wavelengths in the infrared region of 1064 nm and green visible light of 532 nm. A maximum of 10 laser pulses with a frequency of 1 Hz were used on the substrates with contaminants with 9 μm and 11 μm thickness. It was found that for damage-free laser cleaning of OHP film substrates it is convenient to use a wavelength of 1064 nm, with an energy per pulse of 33.36 mJ and using a maximum of 6 pulses. The advantages of pulsed laser radiation in the non-destructive cleaning of substrates with contaminants and the analysis of the substrate transmittance in the monitoring of lasermatter interaction processes were verified.