Rhetorical devices such as euphemisms (a neutral or positive expression only to avoid negative associations), dysphemisms (produces negative effects in order to change one's outlook), weaselers (watering down or weakening a suggestion to protect it from criticism), downplaying (an attempt to make someone or something less significant), sarcasm, hyperbole (an extravagant overstatement, which can also be used in ridicule), proof surrogate (an expression to suggest something is true without displaying evidence of its claim), apple polishing (ass-kissing without genuine intentions).
Many of these methods and tactics are used throughout political campaigns, product advertisement, commercials, etc... in order to dilute one's perception. I hope that this helps. PM me if you require any more suggestions.