four ideas. change the angle of the shot. if you want that angle then change the position of the glasses in the tent so that the reflection you get is a side wall only and not of corners and holes. third option, put an extra level of diffusers to cover the area that's reflecting poorly, so it's only reflecting a diffuse white surface. this could be tricky though. finally, whenever hear "how do i get rid of reflections?" i instantly think "POLARIZING FILTER!!" the tricky bit about the polarizing filter is that chances are you will be able to see right through the glasses which may not be desireable. this would be less of an issue (reflections generally) if you got rid of the case. the shot would look cleaner and the reflections would not stand out much without the black background as a contrast. then insert the brand name in the picture by itself.