Cat is 12 years old - female - no change to litter location or type in all that time. She has a cat flap to access outside. But in last 2 weeks keeps 💩 on the carpets upstairs and I just can't cope with it anymore - she is eating and sleeping fine no suggestions of distress or illness - it's not diarrhoea. - it's solid. She's not my cat technically - I'm taking care of her for a prolonged period so I'm going to get the owner to sort a vet appointment but in the meantime is there ANYTHING I can do?? Is it just an age thing?