The aim of this study was to develop a natural cleaning agent for the conservation treatment of excavated gold leafed clothing artefacts and to test the stability of its application. To this end, a natural cleaning agent was formulated by mixing the extracts of Platycladus orientalis with natural cleaning aids prepared using coconut oil, rice kernel oil, and castor oil. The prepared natural cleaning agent was found to have better cleaning power and stability as a cleaning agent for clothing relics, compared to Saponin, Decyl glucoside, and Triton X-100, which have been conventionally used as cleaning agents for excavated clothing relics. A comparison of the four types of cleaning agents showed that the natural cleaning agent prepared with the extracts of Platycladus orientalis has significantly better cleaning power compared to three low and high concentration cleaning agents that have been used as cleaning agents for clothing relics. The findings show that the pH of the prepared natural cleaning agent was neutral, ranging from 6.61 to 6.93, indicating very weak acidity, the natural cleaning agent did not cause any pH related problems to the fabric during or after cleaning, and the prepared natural cleaning agent can be used as a stable natural agent for clothing relics because it has better cleaning power than the other conventional cleaning agents even at a relatively low concentration of 0.5% to 1.5%, a treatment time of 30 min., and a temperature below 30°C, a temperature which is not damaging to clothing relics.