Yes the early vedic writings were in Sanskrit. And they were "scratched" on
Ola leaves with a pointed iron stylus. [snip] The scratched letters were
dabbed with a mixture of "lamp" black and oil taken onto a piece of cloth.
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As far as I know, this generally applies to South Indian practice only. The
earliest surviving Skt mss from North India, Nepal, Tibet and neighbouring
areas in the NW all seem to have been written with a pen and ink -- either
on palm leaves or birch bark. The northern style of script would, as has
been mentioned, make it difficult to use a metal stylus because the leaves
would split. While the durability of the palm leaf itself remains
unchanged, the South Indian practice of incising the letters results in
greater durability of the written text for obvious reasons -- the parts of
the ink writing on early mss copies of N Indian origin is sometimes too worn
away to be legible.