I've used this product and in my experience it seems to work well. I remember hearing a sales representative from this product at a show; when questioned about the toxicity of the product, he actually said he would drink some if people were in doubt, and I think he might have if I remember correctly.
When using it, I apply it to the snake and leave the snake in a Sterilite container for about 1 hour. I then soak the snake in water for about 5 minutes. You will see the dead mites in the water. The label says to use it no more than every 3 days, but I have used it twice a day and was able to get rid of mites within 4 days. You also must remember to clean the enclosure. You can actually clean the enclosure with the product. I have sprayed the product on the complete body of the snake's that I've treated, including the face. I have not witnessed any problems. Remember, mites love to hide in the heat pits of snake's. I don't think the directions indicate soaking the snake as part of the treatment, but it helps to remove the dead mites and also the spray that is on the face of the snake.
Sam
