Degrade
Reduce step by step until it stops working; the failure point is the finding.
Photocopy the photocopy until it's gone.
Seen in Alvin Lucier, I Am Sitting in a Room, 1969
Try it on your work
Reproduce the thing you're working on as faithfully as you can, then reproduce the reproduction, and keep going. Stop when the latest copy no longer functions or no longer reads. What survived every generation is the essence; name it.
Tell someone the idea; have them tell it back; take their version as the new original and repeat with another person, or after an hour's gap, for five generations. Write down the sentence that never changed.
Run your process with ten percent less of one resource (time, attention, budget) each round. Stop the round it visibly fails. The last thing to break was the structure; the first was decoration.
How it has been used
Copy the copy, then copy that: Alvin Lucier re-recorded his own voice until only the room's resonance remained. Somewhere in the generations, the essential and the decorative part company. The move forces you to keep going past the version you like, until it breaks.
Where it leads
Grouped under Take something away