1988年考古学家在匹兹科夫（PSKOV）首次发掘出上了一些乐器部件，主要有3件分别由松木、梨木、冷杉木等制成的竖琴琴头，这些都是13世纪的遗物，中世纪的俄国将这种乐器称做“gu－dok”或者“smyk”。用PEG两步法对这些乐器部件进行了成功地保护处理；首先用PEG1500的水溶液浓度由10％递增到55％，再将其转入浓度为50％的PEG5000水溶液中，处理过程中溶液温度控制在35－40℃，最终将溶液温度升至60—70℃，这时PEG浓度为86％，用塑料布套封干燥。干燥效果最好的梨木琴头用新木材修复成一件完整的监琴。 In 1988, archaeologists unearthed some musical instrument parts for the first time in PSKOV. There are mainly three harp heads made of pine, pear, fir, etc., all of which were relics of the 13th century. Medieval Russia called the instrument “gu-dok” or “smyk.” The two-step PEG method was used to successfully protect these instrument components. First, the concentration of PEG1500 was increased from 10% to 55%, and then transferred to 50% PEG5000 solution. The solution temperature was controlled during the treatment At 35-40 ° C, the temperature of the solution was eventually raised to 60-70 ° C, at which point the PEG concentration was 86%, which was sealed with a plastic bag and dried. Drying best pear wood head with new wood repair into a complete supervisor.