Question: I forgot to remove the dry cleaning tags from my clothes before Shabbos. Was I allowed to remove them on Shabbos?
Answer: The Shulchan Aruch (OC 317:3) writes that one mustn’t open a knot that ties new clothing together. The Rema brings an opinion that concurs with the Shulchan Aruch, writing that one mustn’t, therefore, open temporary stitching tying clothes together, etc. He then writes that there are those who allow opening temporary stitching providing one doesn’t do so in front of one ignorant of hilchos Shabbos (See Beis Yosef OC 317:8).
The Taz (317:7) defines a temporary stitch as one that was supposed to be undone within twenty four hours. The Levush (OC 317:3), however, writes that even if the cleaners tied it knowing that their customers wouldn’t open it for a while, that is still considered to be temporary.
The Mishna Berura (317:21) writes that while the halacha follows the Levush, some follow the Taz. Nonetheless the Aruch Hashulchan (OC 317:22) and R’ Shlomo Zalman Auerbach (Shemiras Shabbos Kehilchasa 9:n55) maintain that we follow the Levush.
Following this, R’ Yehoshua Neuwirth (Shemiras Shabbos Kehilchasa 15:63) writes that if one forgot to separate a new pair of socks or gloves, one may cut through the string that attaches them on Shabbos, providing that one destroys the string by doing so. R’ Ribiat (The 39 Melochos p828) adds that if necessary one may even use scissors to cut the tag.
In conclusion, if one forgot to cut one’s tags off before Shabbos, one may do so on Shabbos.