Originally Posted by prepreludesh

The fluid reservior covers are actually there to absorb any drips from leaks that might develop on your clutch or brake master cylinder. Since there is brake fluid in both and brake fluid is known to eat right through paint in very little time, it became a trend to put the covers right around the area where the lid seals it in case there happened to be a drip that might get on your paint somewhere in the engine bay and corrode that area. Not completely a necessity, but it's a trend that alot of people do have on their cars.