Revisions log for Answer #426

I think that frequent high pressure cleaning makes the moss come back faster is a misconception. If the moss was already there, it would show up faster, that's true.

If the stone is altered by high pressure and the pores open, that may be true, but otherwise the most useful thing with moss is to remove it as completely as possible, as it may grow back from the remaining plant parts (which are easier to preserve in open materials than in closed ones).

An effective enemy of moss is dryness ...