Yes you can. You can mail it and payable to:

Save A Pet, INC
67-600 18th Avenue
Desert Hot Springs, CA 92241
Tel: (760) 329-8510
SaveAPetOnline.org

When you send it, be sure to include a note whether it is for the dogs, cats, vet clinic, and what you would like the funds to go to. Be sure to provide your full legal name and address. You will receive a 'taxable donation' receipt back in the mail which is good because the shelter is a 501 c3 non-profit organization. Thus, you can write off whatever it is that you send.