Cruft is unnecessary clutter that tends to form as a side-effect of activity. If, for example, a node's content has been heavily added to by a large number of people, its formatting and continuity may suffer. A little discretionary editing is often in order to make the content clear and understandable.
Note that reducing cruft doesn't mean just mean idly prettifying the text. Your goal, when de-cruft'ing is to make the content more clear and understandable.
This node is a part of the cloud wiki manual.