If traces of urine odor remain on your carpet from an unfortunate accident, that odor may signal to your pet that “This is where you go”. Since many pet urine stains are invisible to the naked eye, you can use a handheld blacklight to spot them. Just turn the lights out and move the blacklight around the room, a few inches above the carpet, until you spot the conspicuous glow of a urine stain. Then tackle the stain immediately.
UPDATE: So I tried this out yesterday: the solution foamed up and clogged the spray nozzle so I couldn't spray it. My next move was to put the H2O2 in the spray bottle by itself and sprinkle the baking soda on top. That worked great! I still have a little ring from the stain by the odor is gone! (How to remove urine stains from a mattress)
Our Little Coop: How to remove urine stains from a mattress