Can you loosen elastic?

Depending upon the material casing around the rubber or spandex, the elastic may easily stretch. When needing to stretch elastic for a craft or project, you can either sew the elastic and stretch it while sewing or apply heat while stretching the elastic.

Does elastic stretch after washing?

It will shrink, but not as much as rayon. However, like rayon, dry cleaning will destroy its stretchability, so use it on garments you plan to launder at home. Elastic should be able to stretch to at least twice its length and still snap back to its original size when relaxed.