The Department of Mineral Resources began restoration work on the Naga cave in the Phu Langka National Park that vandalized by Thai tourists.
The park has been closed since Sept. 8 after the recently discovered Naga cave were defaced by unwanted inscription and graffiti.
Officials conducted survey on the damages at several spots of the rock formations that resemble a mythological giant snake or Naga and were said to be about 100,000 years old.
Turpentine is used to remove paint stains and charcoal writing but the difficulties remain for inscription in the rock surface.
The fossil repair technique is being applied by grinding the same type of rock, found near the cave and making it into the mixture to fill the gouges before letting the nature restore itself.
The Phu Langka park in Bung Kan Province earlier this year revealed the Naga cave as a tourist attraction, featuring the big rock that look like a snake head. Another highlight is the cracked rock, resembling snake scales.