I don't currently have any unaltered dogs but since I do rescue I'm bound to come across one. Just wonder if anyone had knowledge / opinion on this:

http://www.acc-d.org/Esterilsol

My guess you would be injecting something caustic into the the dogs nutz. Another chemical for the liver to break down.

At least with the neutering they're gone not poisoned.

Please visit http://www.arksciences.com/faq.html and you will be surprised. I am part of the Executive Team at Ark Sciences and we routinely toast with Esterilsol at our meetings. Esterilsol is a mixture of Zinc Gluconate and Arginine in water with no preservatives and a pH of 7. They are both supplements you will find in a health food store. Traditionally, chemical neutering was cruel with toxic chemicals being injected into the testicles. Esterilsol is just the opposite. More than 98% of dogs never need any medical intervention after the 2-minute procedure than can be done without sedation in most cases.

I'd rather have the surgery, personally.