Layers of sound

After reviewed my recordings, I found that almost everything I have recorded were made of several layers of sound. I don't think they are mixed with different sound, but layers of sound. It's like when we have several channels of sound, and each channel plays different sound, when they play at the same time, the outcome we will hear is mixed with all the sound from all the channels, but each sound has it's own layer. But is it possible to separate one of the layers out of the recorded sound? I think it will be hard, because when I was recording them, every single layer of sound come to the same track. Computer could not separate the layers, but human brain could still recognise different sound layers inside the track. Hard to take the layer out, but we still can add more layers to the track to make the track more interesting.