We don't know what you're trying to say so it's impossible to correct it, but "clean up nature" means nothing. "Nature" refers to the entire natural world - flora, fauna and everything else!
Do you always go to the same place and try to clean it up? What is that place? A park? A forest? A beach?
I guess the intended meaning is pretty clear to a person of average intelligence in spite of the broken English. What are then better suggestions? To clean up the woods and meadows? Clean up the outdoors? Clean up the countryside? Clean up the landscape?
I feel something is fishy about cleaning up nature, hence I asked.
Perhaps environment is the word you are looking for. Nature suffers in various ways when people don't respect and take proper care of our natural environment.
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