Latin

So, a question for all you Latin scholars out there. What would be good Latin for the famous phrase: "Garbage in, garbage out"? Is it satisfactorily obfuscatory and formal, or is it just too obvious? (I'm thinking of designing a coat-of-arms for the company I work for, and that would be a good motto for the scroll underneath. I imagine at least one of the devices [is that what they're called?] would be a flying pig…)