Possible Clues:

• Obscene material corporations briefly rejected
• Dirty talk that turns stomachs
• Larry Flynt's stock-in-trade
• Corporation's dug up a bit of dirt
• Obscenity makes stomachs turn
• Indecent talk - black mark
• A four-letter word constitutes obscenity
• Flake of soot or indecent talk
• Great literature it's not
• Small soot flake or indecent talk