If your sink is completely full and draining slowly, bail out as much standing water as possible. The reaction works best when it hits the clog directly, not diluted by a pool of dirty water.
Let this mixture sit for at least . If it is a stubborn clog, letting it sit for an hour is even better. how to unclog a sink with baking soda and vinegar
Give it a try before you call the plumber—you might be surprised at the power of a little fizz. If your sink is completely full and draining