Leave the baking soda in place for several hours, then vacuum or shake it out. Human/pet urine or vomit on carpets and upholstery can be trickier. If you can get at it immediately, blot first with a towel, then spray the area with a 3-parts cold water/1 part vinegar solution and blot (but don’t rub). Repeat several times if needed, until the smell disappears.