HI, @kristen2 ! Welcome to the forum!
You can cleanse with sound or use a spray. Just get some fancy lemon and rosemary spray with essential oils or something, and see if you can use that. Salt helps cleanse, too, but I don’t know if you can get away with that. So something like a room spray with lavender or lemon might be best. That is, if you’re allowed to do that. I wasn’t sure.
You can also do a simple prayer. Like to Bast, or Freya for cats, and Hecate, Artemis, and Anubis for dogs. Just a simple “May Bast take you into her loving arms” would be good. I’m not sure if you work with other animals. I have no idea who the patron god of ferrets would be!
There is also a Prayer for the Departed and a Pet Protection Spell on site. They might not be right for what you want, but they may give you an idea of how you can either write or create your own spell!
I hope this helps. And thank you for taking care of all the little fur-babies. You’re an angel.