[en] Surface contamination of PLZT (lead lanthanum zirconate-titanate) hot-pressed ferroelectric ceramics being used as the electrooptic wafers in thermal/flash protective goggles has caused ''mottling'' on the surface of the wafers adversely affecting the performance of the goggles. Mottling describes the nonuniform appearance of the goggle lens in the transmitting (open) and protective (closed) states. Experiments were devised to identify the contaminant and to find a method of effectively removing it from the ceramic surface without changing the electrical properties of the PLZT. Infrared spectroscopy, secondary ion mass spectroscopy, Auger electron spectroscopy and scanning electron microscopy were used to determine the type and extent of contamination and effectiveness of cleaning methods. The contaminant was identified as the residue from an optical adhesive used in processing the wafers. Various cleaning methods were compared: washing and soaking wafers in a 50 percent potassium carbonate/deionized water solution; solvent cleaning with various combinations of tetrahydrofuran, methylene chloride, methylethylketone; oxygen plasma; ultraviolet light. Results indicated that although solvents and potassium carbonate solutions removed the gross contamination there was still a sufficient amount present to cause the ''mottling''. In addition, some adverse effects on the ceramic surface were discovered in the case of K₂CO₃ cleaning. Auger scans proved ultraviolet light to be the most effective method with no contamination remaining after a two hour exposure and no apparent surface damage. A model explaining the behavior of the contaminated surface with respect to various solvents was developed