[el ess A]

While I agree with others about getting foreign objects OUT of the engine if at all possible, keep in mind the idea may be for the OP to get ASSISTANCE in searching for it if the valve cover has to come off.

If the mechanical experience level is low enough to not anticipate the foil incident, then what may be a simple task of valve cover removal to some may be a huge undertaking for those with lesser mechanical skills. Know your limits and know when to ask for help is key in vehicle maintenance.