Brake fluid is very aggressive, if you don't remove the spilled fluid quickly, it is not only fatal for the paint, it can even cause rust holes.
Starting with the 1955 model year, Volkswagen attached a cushion under the brake fluid reservoir that could absorb the spilled brake fluid. Later it turned out that this was not the right solution, because when the cushion was soaked, it still affected the paint. From the 1958 model year onwards, it is no longer used.
For a perfect restoration, a cushion must be present, if not for the spilled brake fluid, then to counteract the vibrations.
Useful information from Paruzzi magazine and from our YouTube channel :
Look for more technical articles on the page Paruzzi Magazine