Although, cleaning tests have been quite successful. Weathering can be minimized with consolidants and avoiding water percolation. Since now the tests were done just in small areas and are monitored once a year. And it is better to have the deterioration on the product recently applied than on the rock itself. Cleaning has its limits.
Inorganic patinas are part of the rock art now.
The removal must stop when the original is threatened. The same criteria to any art piece. Rock retouching, of residues of insect galleries and other superficial deposits or losses, is useful to have a better view. But this direct intervention is important facing a tourist exploration. Biological deterioration is faster than weathering.