I refused to use pof when I was there. It CLEARLY alters the texture of the rock. It fills in all the pore spaces with resin, which will NOT come off without the use of a solvent other than water. The result is a smooth, glassy surface with a much lower frictional coefficient. The only way to stick is to use more pof.
Magnesium carbonate (gym chalk) washes off with water and more importantly is EASILY brushed off to regain the original texture... Bleau is all about texture.
My understanding is that the locals don't like chalk because it is "ugly." Which is apparently why they saw fit to scribble "STOP MAGNESIA" in red marker or lipstick or something at the base of Toit de Cul de Chien and other classic problems last time I was there.
^^^ Nice share!
I've used pof (resin) and still would, but sparingly, mostly to help out with sole adhérence on polished smears. Often apply it on the rubber and 'rub' it in till it squeaks.
I'll be using magnesia on limestone - just can't get used to it on Bleau sandstone.
Not a French jail. This is another controversial and highly emotional topic and it's hard to have a rational discussion without some nationalism creeping in on both sides of the debate. Briefly, pof is dried pine tree resin that French Font climbers wrap up in cloth and smack the rock with to increase adherence. Some French climbers use it instead of chalk - usually older ones; most use both now.
CON: it's cheating; it makes the holds polished and glassy; you need more pof once a hold has been poffed, creating a vicious cycle; it makes the holds black and look like crap. Old French guys use it who climb harder than me. If you use it outside Font you risk bodily harm.
PRO: it's natural; isn't as visible as chalk; pof may prevent the surface erosion of the sandstone "skin" above the crumblier sandstone underneath; its use is recommended over chalk by COSIROC, the local climbing governing body, its use is recommended over chalk by bleau.info website; it annoys the British."
Let us know!