I know there's a concept of en m'vat'lin isur l'chat'chila: one may not deliberately mix forbidden stuff with permitted stuff (or milk with meat, or meat with milk) in such small quantities that the mixture will be permitted. In fact, if one does so, from what I understand, the mixture is forbidden. (As always, consult your rabbi for a practical ruling rather than relying on what you read on this site.)
My question is whether this applies only to forbidden mixtures or even to permitted ones. Can one deliberately mix permitted things together in order to create a mixture that has a certain property, and does it work?
Here are some examples; indeed, an answer that addresses these would be most welcome:
- Suppose one has a set of identical forks, all pareve, and accidentally used one of them with warm meat, causing it to have meat taste absorbed in it. Can he toss the fork back in the drawer?
- Can one mix a small amount of chametz into food before Pesach (when it's permitted) and have the mixture remain kosher for Passover?