In reply to cb_6:
> Seriously though, I'm confused.
You & everybody else. Truth is nobody has any real idea of what's true & what isn't in this area.
Chalk is 'banned' in Bleau because it makes the rock slippery.
people flout this 'ban' presumably because they think it makes the rock less slippery ??
Pof is 'banned' in the UK because it supposedly coats the holds in a layer of resin & yet I see no evidence for this layer in Bleau where it's widely used.
Most of the holds on Southern sandstone are deliberately coated in a different resin in order to try & protect them from wear.
Unless somebody does some actual research we may as well argue about how many angels can dance on the head of a pin.