is this chipping? i think it is

Prepping holds is pretty common and is often necessary. In the area where I live some of the holds can be razor sharp and give you deep cuts. So we take a stone and gently "sand" them so the hold won't cut us. We don't make it bigger or worse, just a bit smoother.

@Malak & Idar, There's different views on this, varying from no chipping to it's chipped, that sucks. My opinion is that it is chipped, but it does not suck. I would never do it myself, but having my fingers cut multiple times over the years, sometimes I would want to do it. Still, for me, the rocks is there. If there's vegetation that is not protected, I will remove it if necessary. If there's no need to remove it. I just let it be. If there's loose rock, I'll try to remove it in a way as safe as possible. If there's holds that are painful, even when climbing barefoot, I'll try to not use it or take the pain. Reasoning behind this, Vegetation can grow back in a matter of days/months/years, the rock cannot. It is formed over hundreds of years by water, air and climate. Exceptions for me. Holds may break, get worse (less friction), and some worst case scenarios where the life of a person is involved.

i am against any type of modification of holds. @idar it's ridiculous what you're doing. you are chipping. the hold on Jade 8B+ is a 2 finger crimper that is very sharp, and after 3 tries or so it cuts your skin. and they did not make it better !! the crux hold on Amandla V14/15 is a very sharp rasor blade ! and it's kept that way... that first time i was not very aware of what this guy was doing, because it was the first time that i see this, and i never had an idea in my mind that people can do that ! i realised it later after he did it... but i won't allow it anymore. i believe he did this because he's cheating... he's weak in the back of his mind. he wants to win in anyway possible, without improving or hard work. yea, some people are like that. i am not, i prefer to get my skin cut 2 times, and the 3rd time, it gets strong enough that it won't be cut anymore in that place. But you never know this thing because that's the problem with kids these days, they spend time training indoors, on skin friendly holds, they are spoiled . and want to change the holds on the rock so they won't be sharp. or whatever.. they don't understand that the rock is not an indoor wall that must remain intact. So the next time you want to make a hold better, because you think it's not appropriate, remember this: you are a coward, afraid of taking the challenge, and you lie to yourself. keep that boulder a grade or 2 harder.. and instead of doing it the 5th try do it the 5th day, or 5th month. ok, i am leaving, whatever you write now, i won't read it, because i don't care about a different opposing opinion. because i know it's wrong. read this and grasp it

You can not set up any fixed rules on what can be done as all cases are uniqe. You can just give recommendations. I think that you can clean everything that you think might brake but a repeater should be very careful of changing the rock. In general, only a brush should be used. I can understand that some FA's sand a razor edge and some don't.  For routes, I would say that harder cleaning is OK since we do not want stones falling in the belayer's head.

@ Malak: you have obviously no idea what I'm talking about..  There are sharp holds, like you say on Jade.. (like i haven't seen Dosage 5 duhhh.. ) , or on Amandala, (Progression) and there are razorblades. Your fingers have obviously not touched Anorthosite crystals. I / we have many routes and bouders that cuts your skin after a  couple of tries, but i'm talking about crystals  that actually will create deep cuts once you try to use the holds at all . You will bleed like a gutted pig even before your first try i over. That mean that you will never ever do the problem. Imagine taking  bottle, breaking it to small pieces , then gluing the pieces on to a hold with the sharpest edges up.. then you have the type of crystals i'm talking of. They can be up to 5 or 6 mm high and can cut you equally deep. They (the crystals)  will eventually break over time so the "end product" is not that different. It is just made climbable for the first people that climb it. The ethics here is that the people that find the problem and clean it,  can prep holds to make it climbable, but the difficulty should not be altered. After that people can't alter or modify any holds, even if it has razor crystals.. 

What always amases me in these chipping discussions is that he people with the least experience in setting up boulders / equipping routes have the strongest opinions against chipping (No changes at all!) and talk about respecting nature. While the people with lots of experience on opening and equiping would rather talk about which changes should or should not be allowed because they know it is all a grey area to make the route climbable. Starting with the very precense of the acces path itself. In my opinion, in sport climbing and bouldering (and most types of climbing) we cannot climb the challenges as posed by nature as such. We change it in a big way before we climb it. First a path to reach the crag, chase away the birds and the bats,  then clean all the loose rock, Put in bolds, then clean the holds. Even after a line is set up we put magnesium all over it, make the holds and footholds slippery and sometimes even polished. So the act of sport climbing has a big impact on the nature. After all this disrespect for the nature I don't think that he nature would mind that the opener changes the rock a little more. It is the people that mind, not nature.