Undo a knot using bobby pins
Bobby pins are fantastic for picking locks, but many people are unaware that they may also be used to untangle complicated knots. When fingernails won’t work, just place two bobby pins inside the knot on opposite sides and gently tug them to release it.
These are very common to find in almost everyone’s house. Just slide two bobby pins inside the knot, grab the laces, and pull them out. Undoing a very tight knot with one’s fingers can be really difficult, so having something to hold the knot more easily will do the trick.