A little sidetracked, but if you are going to use ammonia as a dog deterrent you should use real ammonia, not the sudsy ammonia cleaning solution, and dilute it at least 10:1 with water. You don't need to aim for the eyes. The reason ammonia works is it smells like urine to a dog and being peed on by a larger dog (you with a sprayer bottle in this case) establishes you as the alpha. Be aware that this only works on dogs who are testing you or who like chasing games. Doing this to an aggressive alpha male is just asking for a fight.