An older cat-urine stain has usually had time to soak past the surface fibres by the time anyone spots it, which is why a mark that looked gone last week can still smell the moment the room warms up.

This Extreme version of Simple Solution's Stain & Odour Remover uses the same Pro-Bacteria and enzyme formula as the standard range, concentrated to what Simple Solution describe as 3x cleaning power for tougher, more stubborn stains. It's a 500ml bottle, safe to use on carpets, upholstery, bedding and clothing.

• 500ml bottle
• Pro-Bacteria and enzyme formula
• Described as 3x cleaning power ("Extreme")
• For use on carpets, upholstery, bedding, clothing and other water-safe surfaces
• Aimed at vomit, urine and faeces marks
• Described as safe around pets and children

One thing worth knowing. "3x cleaning power" is Simple Solution's own comparison against their standard formula, not a figure we can independently confirm, and there's no guidance on this card for how long to leave it on an old, set-in stain versus a fresh one. Treat fresh accidents promptly for the best result, and spot-test first on anything delicate.

Who it's for: owners with an older or more stubborn cat stain that a standard formula hasn't fully shifted.