This posting is mainly a reference for myself, because I was looking for this specific issue a couple times.
OpenStreetMap (OSM) is a map of the world, created by anyone who wants to contribute. It so happens that data might be missing (just go and add it, if you see that something is not on the map). It also happens that someone adds too much data.
OpenStreetMap is an awesome project. Contributors constantly improve a online map and add new data, fix items in the map which did change in the real world, or improve the data for a number of projects (1, 2, 3, 4, 5, 6, List) building on top of the map. Being outside a lot, I figured that I can contribute as well. It’s just a question of how to transport the data from “out there” back to the laptop in my office. After probing around and trying a few tools, I came up with 3 different ways, depending on the situation and amount of changes.