Removing reflection in shiny products

Here is an article on how to use the Clone Stamp tool.

I'm not exactly sure what you want to do.  There are probably many ways to remove a reflection.  Most of them require some editing knowledge.  So, to get the result in the following screenshot, I used a couple of methods.

1. On the top edge of the box, I used a Quick Selection tool to select the right-hand part of the box edge, then used Ctrl+J to place my selection on a new layer.  I then manipulated the new layer and placed it over the portion of the top edge containing the reflection.  I actually did this several times to place a number of small pieces in place.  The manipulation also required reversing and mirroring the pixels to fit the curved edge of the box.
2. For the right hand disc within the box, I selected a circle around the top, created a new layer from the selection, turned the circle of pixels around so that the entire disc would be covered without a reflection, then used a mask to block out the reflection.
3. Perhaps the easiest way would be what I used on the left hand disc.  I created a new layer, used a brush to paint the main item color on the new layer, then used a blending mode to make the item more realistic.  Here, I used a lighten mode.
4. Another method would be to use the Clone tool to copy pixels from one area to another.

This is a somewhat crude result, but it gives you some idea of what can be done.  This may also give you some idea that this is perhaps not the easiest job for a beginner.  If you want more explanation on any of these methods, I will be happy to provide more detail.