Yes, I've used a tooth brush, tooth picks etc to flake off little bits. The snails and stuff will help out a little to. How much l.r. vs lace rock? If you have enough you could get an urchin. They will eat coraline but, in the process they'll help it spread around your tank . If you don't have enough though they'll eat it all so. As another idea you can get some l.r. thats covered with coraline and scrape it off with a plastic knife etc then pour the liquid into your tank. If you don't have anything in there but, rock turn off your power heads for a couple of days to give it time to stick.
Hth
Chris