How do you manage your abandoned code?

There are times that I have invested quite some time into a chunk of code and realize that sometimes its just better to abandon it entirely and try a different approach. This code often contains useful techniques that don't always get carried over to the final release.

The thing that bothers me is that many times I suspect I wasn't too far off in solving the sticking point, and I sometimes find myself wondering if my initial approach wasn't the better one.

My current solution is to try to move all such code into a private repo for later review, but I don't always have the head-space to interrupt my work and manage that overhead.

What are your techniques or tools that you leverage in managing your abandoned code? Do you commit it somewhere for a later review by yourself or a team member? Do you just git stash and move on?