Cat urine on your sofa will make the sofa unsuitable for use in short order. Simply cleaning the cushion surface will not suffice, since on most surfaces the liquid very quickly penetrates into the padding beneath. Use a black light to pinpoint urine if it's not apparent.
Blot up as much of the urine as possible with paper towels if it is a fresh stain. Newspaper will also work well to absorb moisture. Continue blotting, using fresh paper as necessary, until the paper no longer absorbs any liquid.
Remove the cushion cover if possible and machine-wash it. Add a cup of vinegar to the rinse cycle to help with odor removal.
Sprinkle baking soda on the cushion to soak up any remaining urine and to neutralize the acid in the urine. Allow the baking soda to sit for three hours to give it plenty of time to absorb. Brush or vacuum it off the cushion afterward and discard it.
Fill a spray bottle with equal parts white vinegar and water. Spray the solution on the stain, soaking it thoroughly. Work it into the stain using a scrub brush.
Allow the cushion to dry thoroughly. Setting it in the sun will speed the process. Place the cover back on the cushion and enjoy your clean sofa.
- For older stains, several treatments may be necessary to remove all odors.