Putting stuff in a small plastic bag with a fan in the background. Recorded with a bluesnowball w/ a pop filter. At a distance of 10inch/23cmsoftware used reaper.
Some birds recorded in stereo in the woods near my house. It is some low frequent sounds in background but you can just send it through an equalizer with a highpass-filter and then get rid of it.
This is a japanese bamboo flute. It is called shakuhachi. Recorded in the summer with the windows open, you can hear lots of little insects in the background. Try some reverb and delay on this one !.