Surely if its in common use and is well known, then there's plenty of evidence of prior work? That would make it unenforceable surely? In which case Colgate hav

Surely if its in common use and is well known, then there's plenty of evidence of prior work? That would make it unenforceable surely? In which case Colgate have just spent a smallish chunk of money on publishing how to make a powder that makes teeth cleaner. Funny, but not especially "...another example of companies trying to use patent laws to lock up widely known knowledge.."