Mouthwash: Use this at your peril! The majority of mouthwashes contain very high levels of alcohol which actually WORSENS bad breath!
Breath mints and sprays: A pleasing smelling mouth doesn't nesessarily mean that you have a healthy mouth. Mints and spray temporarily mask your bad breath, but provide a veritable feast for bad bacteria that will significantly worsen the probelm.
Chewing gum: Chewing gum does increase salivary juice flow, but only masks bad breath. Try drinking water throughout the day instead, which keeps you in good health as well.
Chewing tobacco: Smokeless tobacco is a health hazard and causes gums to dissolve and increases the chance of losing the material that hold your teeth firmly in your mouth, and, worst of alll, causes oral cancer. Avoid at all costs.
Vodka, martinis, or whiskey: Alcohol is a drying agent, and will further increase the problem by making your mouth too dry (which results in accelerated growth of bad bacteria).
Brushing with cleanser: Unbelievable as it sounds, many people have tried to brush their teeth with household detergents, bleach, and other cleaning products! They "reason" that, if those things do such a good job cleaning their house, maybe they'll do a good job cleaning their teeth as well. However, many of these products are poisonous and, in some instances, fatal. They should never (ever) be put in your mouth!
Intestinal cleansing methods: Bad breath doesn't originate in the stomach or intestine. It originates in your mouth. Internal cleanses might be good for overall health, but don't expect them to eliminate your bad breath.
Tongue piercing: As with any wound on your body, tongue piercing creates an entry-point for bacteria, and that has the potential to worsen your problem considerably! If you think "ordinary" bad breath is bad, imagine what it will be like if you have a smelly infection in your tongue as well!