Now, as to peeing on a sting...
Virtually all toxins in our tanks are proteins. Anything that breaks down or modifies proteins will help.
Think of clear egg white. Mostly protein. When it is broken or modified it becomes white and firm- or as it is correctly referred to, denatured.
What processes can cause that. Heating for one (hence soak fingers in hot water, as hot as you can stand).
Another, acid or alkali.....mix eggwhite with lime juice. It will set.
Another would be ammonia. This is where the peeing on jellyfish stings comes from. However, we dont produce ammonia but urea/uric acid, which may also do the job. - Im unsure.
Anyways, those are the tried and true methods.
--if it works on a bee sting, it will probably work on a "tank Sting"