First of all...good idea. There can be a lot of information that can be gleaned from metadata, and if you are sharing the files outside of your company, you don’t necessarily need all of that information getting into outside hands.

Microsoft has a guide on how to minimize metadata in Excel workbooks. It’s not the easiest thing to do, and depending on how much you want to remove, it can be a multistep and time consuming process.

Here is a link to the guide: https://support.microsoft.com/default.aspx?scid=kb;EN-US;223789