 clean climbing is a rock climbing term that describes techniques and equipment which climbers use in order to avoid damage to the rock. these techniques date at least in part from the 1920s and earlier in england, but the term itself may have emerged in about 1970 during the widespread and rapid adoption in the united states and canada of nuts (also called chocks), and the very similar but often larger hexes, in preference to pitons, which damage rock and are more difficult and time-consuming to install. pitons were thus eliminated in north america as a primary means of climbing protection in a period of less than three years. due to subsequently major improvements in equipment and technique, the term clean climbing has come to occupy a far less central, and somewhat different, position in discussions of climbing technology, compared with that of the brief and formative period when it emerged four decades ago. ==rock preservation== drilled and hammered equipment such as bolts, pitons, copperheads and others scar rock permanently. various protection devices became widely available around 1970, which were far less likely to damage rock and much faster and easier to install, when used sensibly. such "clean" gear, as of contemporary times, now include spring-loaded camming devices, nuts and chocks, and slings, for hitching natural features. contemporary alternatives to pitons, formerly called "clean climbing gear," have made most routes safer and easier to protect, and have greatly contributed to a remarkable increase in the standards of difficulty notable since about 1970. pitons are now regarded as highly specialized equipment, needed by a small minority of climbers interested in routes of peculiar difficulty. even clean gear can damage rock, if the rock is very soft or if the hardware is impacted with substantial force. a falling climber's energy can drive a camming device's lobes outward with great force. this can carve grooves into the rock's surface, or, if the cam is in a crack behind a flake, the expansion can loosen the flake and eventually (or suddenly) split it off. wedges (nuts) can also be forced into a crack much harder than the leader intended, and cracks have been damaged as cleaners try to chisel or pull stuck nuts out of their constrictions. in very soft rock, nuts and cams both can blow right through the rock and out of their placements, even with forces as small as those generated by tugging to "set" the piece. although hooks are often categorized as clean, they easily damage soft rock and can even damage granite. ==histo
Types_of_climbing