I'm sorry, but I don't know the answer to your question.Do these work via some adhesive plastic (rather than a layer of some sticky substance), that will preferably stick to very smooth/polished surfaces? Because I'd be looking for a convenient solution to cover (web)cam lenses on notebooks et cetera - so "reasonably adhesive" and "easily removable, without leaving any residue" would be the attributes I'd foremost look for, and "reusable" wouldn't harm either...
Greetings from Munich!
Manfred / lini