Go to any "nature spot" --e.g., scenic area, beach or lakeshore. If you can take a little extra pity on it, carry away those "unnatural" paraphernalia, and let your bag fill up a little heavier, you can reduce considerably the blemishes that would be left behind.
到風景區、海濱、湖邊等一切屬於「自然」之地，若能稍加憐惜，順手攜走這些不屬於「自然」之物，讓行囊多添一點點負荷，卻可以減少許多後遺症。