Polishing a turd

I try to stay away from idioms and other bits of faux-wisdom but one that actually stuck with me from recording/songwriting circles is “you can't polish a turd”. 

Which I always took to mean “if your song isn't any good, no amount of production or recording wizardy will make it good”.

So episode 19 of season 6 of the Mythbusters is awesome: they polished some animal shit. Which may forever alter my songwriting process. Kudos.