Seen people doing things like recording stones, metal pieces, and such.. Even Grunt already years ago, in albums like Petturien Rooli for example, some sounds would be generated with wheelbarrow filled with water and stones, mic'ed and you would get odd, almost unrecognizeable sounds you quite can't get what exactly it is, what type of efx or gadgets... but there was none really. Just the sound of "objects".
Thank you, all you posted is interesting and helpful. For the wheelbarrow recording, did you use a contact mic (on the wheelbarrow itself or the objects in it) or a regular microphone?