Christi, I agree with Watch. Salt is good with a plain water cleansing enema, but for a coffee enema, coffee alone is best.
Of course you can always precede or follow a coffee enema with a salt solution (1 teaspoon per pint of filtered or bottled water at 103 degrees F, 39.5 C) cleansing enema if desired. A cleansing enema prior to the coffee enema can help remove waste matter that can prevent absorption of the coffee through the walls of the colon, and afterwards help remove any residual toxins released from the liver into the colon.