We don’t advertise Eco Orange as a cat deterrent in yards or anywhere for that matter. In fact, we heavily promote Eco Orange as being pet-friendly. As such, animals won’t in anyway be repulsed or endangered by Eco Orange no matter the dilution. However, we’re not surprised that folks want to use our versatile cleaning agent for cross-purposes.
While it’s been documented that cats don’t like citrus, citronella, eucalyptus, lavender, and vinegar, try using Eco Orange at 10:1 and add vinegar to it; that sounds like a lethal smelling potion. Though unsightly, you could also try sprinkling actual orange and lemon peels in the cat-traveled areas of your yard — maybe a combination of all the above for a full frontal assault on those pesky strays. We have also heard that lavender Febreze sprayed in the areas you want to protect might work.
Bottom line: Eco Orange could be an expensive solution to this problem. Stick to using it for cleaning.