Got a can of degreaser, do I just spray it all over the valve cover and sides of the engines that I can get to? It says on the can to be careful not to get on any electronics, anything I need to be especially concerned about?

Also, at the auto parts store they were recommending some type of UV dye you put in your oil, that you can see better where it is leaking from. Is this stuff good or a waste of money?