Someone who doesn't know what a Curves layer is, is very unlikely to have the faintest idea what a Smart Object is...
Silver.hunter, that image is very easily cleaned up with a simple Curves adjustment. Nothing more is needed. If you can't get it right, it's because, well, you haven't got the right curve. Try again, or look up some tutorials. Curves is such a basic and central function in Photoshop that you need to figure it out anyway. If Photoshop is a car, then Curves is that big round thing right in front of your nose.