how to swap scents properly

I have two cats, Rex and Blue. Rex is 4 and Blue is 2. They are behind a door right now with a towel stuffed under it. I want to start the scent swap. How do I do this properly? I read you have to wait a certain amount of time but I don't see the exact steps anywhere.

Oh my gosh, welcome to the chaos! I did this with Cleo and Zeus and it took forever but it worked. You just take a little towel or a soft toy that has been in one cat's room and put it in the other's room. Wait 24 hours. Then swap it back. Do not open the door yet! Check out setting up the safe room for more on the setup.

The duration depends on the cat's baseline stress level. For Rex, who is aggressive when scared, I would use a 12x12 inch piece of fabric. Leave it in Blue's room for 48 hours, not 24. Monitor Blue's behavior using the criteria in reading the body language. If Blue is hiding, extend the time.

Make sure you are using separate items. If you use the same toy, you are mixing their scents too fast. Use one for Rex and one for Blue. Also, if they start hissing through the door, stop. See check the thyroid first to make sure it isn't a medical issue.

Okay, so separate items. I have a blue toy and a red toy. Do I leave the blue toy with Blue and the red toy with Rex? Or does it not matter?

It matters a lot! The blue toy should stay with Blue so it smells like him. The red toy stays with Rex. You are swapping the *smell*, not the object. If you mix them up, it gets confusing. Also, keep feeding them separately like in feeding them apart so they associate good things with being alone.

Agreed. The spatial association is critical. If the scent source moves, the cat may interpret it as a threat entering their territory. Keep the items static for the full 48 hours. If you see any of the signs in reading the body language, reset the timer.