Get a copy of the MSDS (Material Safety Data Sheet). It will list what is in the product (although some propritary compounds may be listed as such). You can get it from the maker, or where you buy it.
The store clerk may not know anything about it, but management will, they have to have them "available" by law.
Ammonia is NH4 and might be listed that way, even on the can
Another possiblity is your can is bad, producing an unusual smell. Contact the maker.
All else being equal (and it almost never is) bigger bullets tend to work better.