I'm not sure which catagory of law this falls into. I've discovered a way to reuse a rather expensive product and wonder if it would be legal to sell the instructions online. While I'd rather not divulge the details of the particular product now it would be akin to instructing someone how to effectively clean a filter made exclusively for use with a specific brand of air cleaner rather than having to buy a new one. In the hypothetical exanple of the filter could I be sued by the manufacturer of the air cleaner?