How do I clean a tileset in only a few clicks?
Well that's rather easy! You just a cleaning backdrop! Register the one above as cleaning backrop.bmp
Then go under custom.exe and edit maptilesets. Pick up the one your want to clean/ to free. Go down to "replace current tileset" (be sure no to append a new one) and import cleaning backdrop.bmp
Here you are! You have already finished! Your tileset is cleaned now! You can start to draw a new one!
Note that you have already placed buildings on the map this method won't it you because what you are going to draw may appear on the map (the linked between a given part of a tileset and its position on the map is not broken) In this case it is better to try to embetter the grafics and made some modifications everydays : you will go quicker! (and it will improve your drawing skills)
So when do you have to use the cleaning backdrop? Well, you can use it when you import an already made tileset (one for Wikings of Midgard for example) and you realise that finally you don't need it. You have not used it yet and don't intend to.
Instead of copying and paste parts of tileset for 14 minutes just use this method!
It also works with backdrops!