OK, what exactly are they? well chemically anyway… I know what they are in very general terms.
I have heard claim they keep away insects of all kinds.
Is this true and how does it work?
If I dropped a few in flower bed would that be a very bad thing enviromentally?
Thanks in advance,
Osip
discusses both types, napthalene and paradichlorobenze, of mothballs.
I’m not sure why you would want to drop a few in a flowerbed. It’s doubtful that they’d work to kill moths in such a well ventilated space. paradichlorobenze might kill your plants though. Try it and see…
And they smell damned funny, if you can get their little legs far enough apart 
“Moth Balls” is the common name for naphthalene, also known as albocarbon, mighty 150, mighty rd1, moth flakes, NCI-C52904, white tar, naphthalin, naphthene & camphor tar.
The chemical is toxic by inhalation or ingestion and may also be a carcinogen. It sublimates (goes directly from solid to gaseous state) at room temperature, and the resulting vapours are what dooms cooties of all kinds. I’ve been told by vets that it even clears carpets of flea infestations (even the eggs), but have not needed to try this as of yet. Supposedly, just sprinkle some moth flakes on the carpet, seal up the room & the heavy noxious vapours will exterminate the little buggers.
Not sure what it would do for plants. I can’t believe it would be any good for them.
[Duck Duck Goose hat on]
http://www.google.com
search “moth balls”
get results
[Duck Duck Goose hat off]
This one was easy. (No offense intended to DDG.)
-Rue.
Man! Squink beat me to it. That was my link too.