I must agree with the opinions of everyone else, chalking the rock art was something that was done along time ago before we knew what the effects on the stone were. Now we know better, we all want to see the RA, that is why we do it, but we must realise that we also have to look after it, where possible to extent its life for future generations. Even when we use water, brushes etc we need to be careful, anything that makes contact with the rock surface is damaging it. So please be careful when doing anything with the rock art.. and NO CHALKING!!!!!!!!!!!!!!
Please follow the instructions from Jan in his reply.
An example of how delicate rock art can be,..
In 1967, R morris uncovered a panel at Kirkmabreck , Dumfries and Galloway. The panel had nice rings, but within 5 years of the panel being exposed the southern ring was gone, weathered off. As a result Morris recovered the panel to protect for further generations.
So everyone please take care with our precious rock art, just because its rock, doesn't mean you can do anything to it you want.
Wolfnighthunter (Brian "Blokey" Kerr)