In my experience, there's usually a subtle release mechanism or button that you need to squeeze and the physical key will slide out readily. On some of mine, t

In my experience, there's usually a subtle release mechanism or button that you need to squeeze and the physical key will slide out readily. On some of mine, the physical key is also the pry-tool used to open the body of the fob for battery changing. :) On my Toyota, this mechanical key can be used to lock the doors while the engine is running (pitstop mode), which is otherwise not possible. On my friend's Mercedes, it does not respond to the mechanical key (wait, what?) while the engine is running.