Putting Lipstick on a Pig

A co-worker recently pointed out a sentence he read in an email: "That would be like putting lipstick on a pig."



I like UrbanDictionary's definition best:
A term used by many, generally in reference to someone who may be trying to make something or someone look appealing or attractive when it quite clearly will not work, or will only deceive the dumbest of people.

Example:

Used car salesmen have a reputation for "putting lipstick on a pig" because they can often talk you into buying a car that might just be a piece of junk!

Read here about how Obama put the phrase back into popular use in 2008.