Hello! I recently bought a back-cover for my iPhone 4S. This is not meant to replace the iPhone backside glass but merely to cover it, preventing scratches and such. Unfortunately, I am noticing that the sides of the cover are beginning to loosen up. It haven't come to the point where the cover is falling off but I want to research my options already now. So I was thinking of just applying some more glue, perhaps some stronger glue, to make it stick better to the glass. I do not want to leave any marks on the glass and I also want the cover to be removable fairly easially. Does anyone know of a glue/adhesive that I can buy? Thanks!