An animal that has weed on the same corner three times is not being defiant. It is reading its own signposting and doing what the sign says, which is why shouting achieves so little and why changing what the corner smells like achieves more.

This is a deterrent rather than a cleaner. The active idea is a strong mustard scent that makes the treated spot unattractive to a dog or a cat, and the maker's own note is that the initial odour is unpleasant to people as well but disappears within a few seconds, leaving the deterrent effect behind on the surface. The formula is described as non-staining and usable anywhere in the home, and it comes in a 500ML bottle, which is a lot of applications.

• 500ML bottle
• Deters a dog or cat from urinating and soiling where it is applied
• Works on a strong mustard scent
• Described as a non-staining formula
• The initial smell fades within a few seconds
• For indoor use anywhere in the home

There is no ingredient list for this at all. The only thing named anywhere is the mustard scent, and "100% pet friendly" is printed with nothing published behind it — no ingredients, no list of surfaces to test first despite the non-staining claim, no reapplication interval, and nothing about homes with birds, fish or small animals in them. The other honest limitation is what it does not do: a deterrent does not remove what is already there. If the spot still smells of urine to the animal, an enzymatic cleaner is the first job and this is the second, or you are spraying mustard over a signpost that is still up.

Who it's for: anyone with one problem corner — a rug, the base of a door, a particular chair leg — rather than a house-training problem, and people who have cleaned a spot properly and want the animal to stop going back to it.