Hi, i have a small problem. I would like to delete some dublicate objects and i don´t find a way to properly do this. I Rhino i say “choose dublicates” and i delete them. Is there something similar in Blender? I found an old thread saying “shift + f9” would help but there i would habe to choose every single dublicate. This can take a while in a bigger scene 
Thanks for your help 
^From your unclear description (Could you post a .blend/screenshot?
) I would say “Shift+RightMouse” to select anything and hit “x” to delete the selected objects.:eek::eyebrowlift2:
Objects have names and if these are duplicated objects names usually are “name.xxx” where xxx is some number.
Menu Select has option Pattern: write in part of the name, add asterisk (which probably got deleted), hit Enter. Unselect one object (Outliner, 3dview) and Delete.
I think you idea for an example is a good one 
So this is my example.
I have 36 Spheres in my Example Testrender 1. These are all different objects, but they do have the same material. The Names are Sphere.001 to Sphere 36.
Then i work with these and for whatever reason i make copies of some of them. Now i have 41 Spheres, but my render only shows 36. 5 Spheres are in the same location as another and i don´t see any possibliity to “track” these down, because they have different names. The only thing i see is, that this leads to problems while rendering (have a look at the “darker” shadows in my rendering).
Do you know a possibility to track these down to erase them? I would be glad if there would be an option like “Remove Doubles” for Objects.
Attachments
Quick Blender render probably would show some artifacts if there are several objects in one place if Cycles does not tell that.
You could spare one object and use Array modifier to recreate scene.
Select all, join into one object, remove doubles and separate by loose parts - quick and dirty way.
Some scripting probably would sort them too.
You could join all the spheres, then in Edit mode Remove Doubles, then separate the objects again (P, by loose parts).
Then if necessary, Ctr Shift Alt C for getting the individual origins back to the objects.
This way the objects should keep their individual materials and UV’s…