Final cut has a mask tool that lets me mask out parts of a clip. However I suspect this concept does not exist in premiere? It seems that masks can only be applied to an effect? My current approach is to do a mask on an opacity 100 clip....but I want to know if there is simply a mask that does not require an effect to be applied?
Simplest way is to use the mask feature from Opacity.
Opacity is an fixed effect of the clip.
As Ann says, use the basic opacity controls usable on any clip ... go to the Effects Control Panel and twirl down Opacity. You'll see the mask tools there.