The holiday creative challenge started with attempts to transform found objects into ornaments instead of buying (and then discarding) store-bought decorations. Through the years, I've used chandelier crystals found in a box in the attic left by the prior owner, nails /strings of nail gun blanks, steel scouring pads, insect screens, HVAC ducting (last images below), and old mini-flower pots salvaged from a neighbors barn.
It gets more fun every year, and we've avoided lots of waste. Good for the soul and the planet!