U.K.-based Compound Security Systems Ltd. sells a device to repel loitering teens with a frequency adults can't hear.

WSJ: A California City Is Into Tweeting��Chirping, Actually��in a Big Way

So EBI has developed a strain of bacteria that gobbles up the compound in wastewater collection systems by injecting the microbes right at the site.

FORBES: Germ warfare

In China, they use artillery shells, rockets and airplanes to spray existing cloud systems with silver iodide, a compound that triggers moisture in the clouds to form ice crystals, which then fall to earth as snow or rain.

WSJ: Blizzard Renews Storm Over China Making Snow

At some outfit designated by three initials--DRG Systems, AZD Marketing, MLF Solutions--or at one of those compound-named firms with a stray capital letter in the middle: SignRave, MedScie, MerchanDesign.

FORBES: Magazine Article