Removing concrete from stone without damage?

Question

my back garden was covered with concrete and as we are doing up the gardeni was cleaning the concrete on the patio area and i accidently chipped some of the concrete.

underneath there are pretty patio stones in red and white and although it was fairly east to clean the concrete from the red stones its hard to see what im doing on the white as the concrete was also white.there are pattened grooves in the stones and i was wondering if there was an easier way of removing it other than the chisel (which i have been using) and which wont damage the stones.

any help is appreciated,thankyou:)

Answer 1

SLEDGEHAMMER!

(gently)