Chalk & Chalk Bags
"John Allen (16yrs) frees Great Wall but uses chalk" ran the headline in Mountain in 1975. Troll's first chalkbag marketed some years later carried an advisory note sating that it was, "Only for use on routes of 6a and above".
Nowadays chalk is common-place on Diffs and Severes and is as much a part of climbing as rope and rockshoes - it stops your fingers from sweating and slithering off small holds and is usually carried in a chalkbag. At climbing walls chalkballs must be used rather than powder or block chalk - these cut down the dust.