Related על ביצה 62:17

Regarding closures on the ground, the Sages agree with R. Meir that one may loosen, dissolve or fray, but one must not cut. But on the Sabbath, one may loosen and dissolve, but neither unravel nor cut. If the closures are on vessels, it is lawful on the Sabbath; and you don't even have to say: on a holiday.