Its not easy to explain,but,you know,there are a hundred thausend Peaces of satelites and Rockets flying in Space around the Earth and we dont know when what fells where down.
Science cant give an Answer,but the swiss can 
They start a cleaning Program.
Shoot a collector in Space who flies with a Speed of 28000 km/h around till it gets a peace,pockets it in and comes back where it gloss away before it hit Ground.
not cheap.Just around 10 Mill Swiss franks,and they dont say how much after the Prototype is tested.
Think we need a Science Forum
You are right.
On each Fly it brings back 1 Peace Rubbish, 
if it catches one 
i dont know why they are messing about like that when they have thousands of tons of explosives left over from the war dumped in the lakes, which are all leaking and affecting the fish. they seem to think its so unstable they will have to freeze it to move it.