Vinegar can be used on carpets and upholstery, but it's important to use it cautiously and perform a spot test in an inconspicuous area first. Vinegar is acidic and can potentially discolor or damage certain types of carpets and upholstery fabrics. It's generally considered safe for use on synthetic fibers, but natural fibers like wool or silk may react differently. Dilute vinegar with water in a 1:1 ratio before applying it to the affected area. If there are no adverse effects, you can proceed with using it to clean and deodorize. However, it's always a good idea to consult the manufacturer's guidelines or seek professional advice if you're unsure about using vinegar on a specific carpet or upholstery material.