using old threads
agree with the snap test and also with using thread on wooden spools as decorator items in a glass jar. However, if you have old thread on plastic spools and want to make use of it, unroll it from the spool and keep it in a baggie until you get the amount/colors you want, then sandwich them between layers of wash-away stabilizer to make decorative thread lace - sample photo attached - then use the lace to decorate bags, clothes, etc, or stitch to background as in photo as wall hanging. As shown in the picture, add other items of interest if desired - this one contains hexagons from an old, unusable GFG made by my own grandmother, some feathers, bits of vintage tatted lace, beads (added after adding it to background), silk ribbons, etc.