Hopefully you'll take the chance to show yourself and others how much and how quickly your skills grew from that point forward.

Also, if you have the time and will to do it, you could always contribute cleaner code to any project that's still using ugly code you contributed.

I tend to be a hit-and-run Open Source contributor myself. I'll find a solution that almost meets my needs, customize it, use it in-house or for a client, and contribute back what's useful to the project. Then, I'll go on to deal with another project for another client. Sometimes my code is refactored, rewritten, or flat out removed in favor of another approach by the time I get back to a project and see what's become of it.