This is a specific conversation about Pet stain and odour removal — what actually works — ask about yours and get one honest answer for your exact situation.
inparticular.ai
Years of layered odours from two elderly cats and a Bichon Frise in one room is a tough one — that's multiple animals, multiple stain types, and deposits that have built up deep into whatever surfaces are in there. The only products that permanently eliminate pet odours are enzyme-based cleaners; anything else masks the smell temporarily, which is exactly why your pets keep returning to the same spots. Before I point you to the right product: is the room carpeted, hard-floored, or a mix? And are we dealing mainly with urine, or is there faecal or vomit residue in the mix too?
It's mainly carpet with one rug. Mostly urine from the cats, but the dog has had a few accidents too. Some of it goes back years — I've tried sprays before but the smell always comes back, especially in warm weather.
inparticular.ai
That warm-weather return is the classic sign that the urine salts are still deep in the carpet fibres and underlay — heat activates them and the smell resurfaces. Standard sprays won't touch that because they're not breaking down the uric acid crystals, just covering them. Tell me a bit more about the dog's accidents — is the Bichon fully housetrained now, or are there still fresh incidents happening? That changes whether we're in maintenance mode or still dealing with active soiling.
He's mostly sorted now, maybe the occasional accident. The bigger issue is the historic build-up from the cats — one of them has kidney problems and goes more frequently.
inparticular.ai
Got it — so the priority is tackling years of concentrated cat urine, with some dog urine layered in, on carpet and a rug. Cat urine is particularly stubborn because of the felinine compounds in it, and elderly cats with kidney issues produce urine that's even more pungent. For this situation I'd go with Simple Solution Extreme Pet Stain & Odour Remover — it's a high-strength enzyme formula specifically rated for set-in, multi-layer stains, and it's widely used in rescue centres for exactly this kind of long-term accumulation. It comes in a large trigger spray (up to 4 litres) which you'll need given the scale here.
How do I actually use it on old stains? Do I just spray it on?
inparticular.ai
For set-in stains you need to saturate, not just mist. Soak the area so the enzymes can reach as deep as the urine did — if it soaked through to the underlay, the cleaner needs to get there too. Then cover loosely with a damp cloth and leave it for at least 10 minutes, ideally longer. Don't scrub while wet; blot from the outside in. Let it air dry completely — the enzymes keep working as it dries. For the worst spots you may need two or three treatments a few days apart. One thing to avoid: don't use it alongside any other cleaning product, especially anything with bleach or strong fragrance, as that deactivates the enzymes.
That makes sense. Will it be safe for the cats given one of them is already unwell?
inparticular.ai
Yes — Simple Solution Extreme is non-toxic and pet-safe once dry, so your cats can be back in the room once the treated area has fully dried. While it's wet and you're applying it, keep them out just to stop them walking through it and tracking it elsewhere. Given your cat's kidney condition, that's the right instinct to check, but the formula is water-based and enzyme-driven — no harsh chemicals. Once you're on top of the historic build-up, a smaller bottle kept handy for fresh incidents from the cats will stop things layering up again.
