I know that George Allen participated in this process recently, by proposing a series of tariff exemptions on small kitchen appliances like toasters and electric knives.
The article points out that these special exemptions are a gravy train for corporate lobbyists- they're easy to get through legislation, relatively innocuous-looking, and create immediate tax savings for their corporate clients. But they wreak havoc on American business trying to compete in a marketplace impacted by special deals for foreign imports, and they cost the government millions each year.
Tax breaks for toasters sticks it to American business and taxpayers at the same time. This is yet another good reason for massive change in the Senate and House this year.