What is the best way to sell an idea to a manufacturer?

Check the manufacturer's website to see if they accept outside submissions most companies do not. If they do accept "concepts" from outsiders, they are typically interested only in ideas that have been patented. That way, what you claim is yours is well defined and they cannot be accused of taking your idea from you. Thus, your best option is to file a provisional application in the US Patent Office (www.uspto.gov) disclosing your idea how to make and how to use it. Then you will at least be "patent pending" for the one-year lifetime of the provisional application and a company might be willing to review your idea as disclosed in that application.

The best way to sell an idea to a manufacturer is to patent an invention that incorporates the idea.

This is a tough question and many people are grappling with trying to figure it out. The answer may depend upon the particular technology involved but this is a general answer. I have worked in the corporate Patent Departments of several large companies. It is common for them to receive inquiries from outsiders on a regular basis. From their perspective they are doing you a favor by reviewing your technology. Let me explain. These large companies have what they consider to be top level technical staffs continually trying to develop new products for them. It would be a disaster for them to be about to launch a major new product that they developed, and then they receive an unsolicited disclosure for the same technology from an outsider. They will find themselves in major litigation for stealing technology that they developed. Accordingly, many companies are not eager to review technology from outsiders. Of course, from your perspective, you are doing them a favor by offering your technology to them. What you will need to do is contact competent legal counsel and search to see if anyone else has filed any Patent Application on your improved technology. If not, you should file a Provisional Application. This process should not cost you more than $2500. Then you should contact the companies that are already in the market. You will need to sign an agreement that you will be relying on your Patent Rights if any controversy arises.

You will have to use a non disclosure or confidentiality agreement or file a patent. Other than threat there is not much else i can offer in the way of protection.

Patent your idea, if possible, and then approach the other manufacturer with your product. If you can't or don't want to patent the idea, you can still show it to others as long as they sign a nondisclosure agreement first. Should anyone choose to license your idea, they will sign a contract with you and pay royalties or possibly one lump sum. You can choose to donate some or all of that money to the charity of your choice